Phase 9: version message (FR-13)

- ใส่คำอธิบายแบบ commit message ได้ทุก flow ที่สร้าง version (Save & Version / Start Versioning / generate จากเว็บ) + แสดงใน version history ทุกหน้า
- backend: DocumentVersion.Message (varchar 2048) + migration AddVersionMessage + BadRequest ตรวจความยาวก่อนแตะ MinIO (กัน 500 + orphan object)
- add-in: ConfirmVersionDialog เพิ่ม textarea (Start Versioning ใช้ dialog ด้วย) + แสดง message ใน VersionHistoryPanel
- web: ฟอร์มสร้างเอกสาร + หน้า detail แสดง message (desktop truncate + tooltip, mobile เต็มบรรทัด)
- sync เอกสารทั้งหมด: spec v5 (FR-13/AC-16) + plan Phase 9 + acceptance-review 1–16 + README + CLAUDE.md + web/README
- tests: backend 52 / addin 50 / web 36 — เขียวทั้งชุด

Co-Authored-By: Claude <noreply@anthropic.com>

backend/WordVersioning.Api.IntegrationTests/TestDtos.cs

@@ -9,7 +9,7 @@ public record UploadVersionResult(Guid VersionId, int VersionNumber);
 
 public record GenerateResult(Guid DocumentId, Guid VersionId, int VersionNumber, string DownloadUrl);
 
-public record VersionItem(Guid VersionId, int VersionNumber, DateTimeOffset CreatedAt, string CreatedByUserId, string ContentHash, JsonElement? Fields);
+public record VersionItem(Guid VersionId, int VersionNumber, DateTimeOffset CreatedAt, string CreatedByUserId, string ContentHash, JsonElement? Fields, string? Message);
 
 public record TemplateFieldItem(Guid Id, string Key, string Label, string Type, bool IsRequired, int SortOrder);
 
@@ -29,9 +29,9 @@ public record DocDetail(Guid Id, string FileName, DateTimeOffset CreatedAt, Guid
 
 public static class ApiExtensions
 {
-    /// <summary>multipart form ของ POST versions: file + clientVersionId + fields (option)</summary>
+    /// <summary>multipart form ของ POST versions: file + clientVersionId + fields (option) + message (option)</summary>
     public static MultipartFormDataContent VersionForm(
-        byte[] docx, string fileName, string clientVersionId, string? fieldsJson = null)
+        byte[] docx, string fileName, string clientVersionId, string? fieldsJson = null, string? message = null)
     {
         var form = new MultipartFormDataContent();
         var file = new ByteArrayContent(docx);
@@ -40,6 +40,8 @@ public static class ApiExtensions
         form.Add(new StringContent(clientVersionId), "clientVersionId");
         if (fieldsJson is not null)
             form.Add(new StringContent(fieldsJson), "fields");
+        if (message is not null)
+            form.Add(new StringContent(message), "message");
         return form;
     }
 

backend/WordVersioning.Api.IntegrationTests/TestFlow.cs

@@ -46,12 +46,13 @@ public static class TestFlow
     public static Task<GenerateResult> GenerateDocumentAsync(HttpClient client, Guid templateId) =>
         GenerateDocumentAsync(client, templateId, DefaultValues);
 
-    /// <summary>generate พร้อมค่าที่กำหนดเอง (ทดสอบ validation หรือค่าเกินนิยาม)</summary>
+    /// <summary>generate พร้อมค่าที่กำหนดเอง (ทดสอบ validation หรือค่าเกินนิยาม)
+    /// + commit message ทางเลือก (FR-13)</summary>
     public static async Task<GenerateResult> GenerateDocumentAsync(
-        HttpClient client, Guid templateId, Dictionary<string, string> values)
+        HttpClient client, Guid templateId, Dictionary<string, string> values, string? message = null)
     {
         using var response = await client.PostAsJsonAsync(
-            "api/documents/generate", new { templateId, values }, IntegrationTestFixture.Json);
+            "api/documents/generate", new { templateId, values, message }, IntegrationTestFixture.Json);
         Assert.Equal(HttpStatusCode.Created, response.StatusCode);
         return (await response.Content.ReadFromJsonAsync<GenerateResult>(IntegrationTestFixture.Json))!;
     }

backend/WordVersioning.Api.IntegrationTests/VersionMessageTests.cs

@@ -0,0 +1,182 @@
+using System.Net;
+using System.Net.Http.Json;
+using Microsoft.EntityFrameworkCore;
+
+namespace WordVersioning.Api.IntegrationTests;
+
+/// <summary>FR-13 — commit message ต่อ version: รับจากทุก flow ที่สร้าง version (upload + generate),
+/// normalize ว่าง/whitespace → null, trim, จำกัด 2048 อักขระ, echo ใน history (AC-16)</summary>
+[Collection(IntegrationTestCollection.Name)]
+public sealed class VersionMessageTests(IntegrationTestFixture fixture)
+{
+    [Fact]
+    public async Task Upload_WithMessage_PersistsRow_AndEchoesInHistory()
+    {
+        var documentId = Guid.NewGuid();
+        using var client = fixture.CreateClient();
+
+        using var response = await client.PostAsync(
+            $"api/documents/{documentId}/versions",
+            ApiExtensions.VersionForm(
+                TestDocx.BuildPlainDocx(), "doc.docx", Guid.NewGuid().ToString(),
+                message: "แก้ไขข้อ 3 หลังตรวจสอบ"));
+
+        Assert.Equal(HttpStatusCode.Created, response.StatusCode);
+
+        await using var db = fixture.CreateDb();
+        var version = await db.DocumentVersions.AsNoTracking().SingleAsync(v => v.DocumentId == documentId);
+        Assert.Equal("แก้ไขข้อ 3 หลังตรวจสอบ", version.Message);
+
+        using var history = await client.GetAsync($"api/documents/{documentId}/versions");
+        var items = await history.Content.ReadFromJsonAsync<List<VersionItem>>(IntegrationTestFixture.Json);
+        Assert.Equal("แก้ไขข้อ 3 หลังตรวจสอบ", items!.Single().Message);
+    }
+
+    /// <summary>ไม่ส่ง / ส่งค่าว่าง / ส่ง whitespace ล้วน → เก็บ null ทั้ง DB และ history</summary>
+    [Theory]
+    [InlineData(null)]
+    [InlineData("")]
+    [InlineData("   ")]
+    public async Task Upload_BlankOrMissingMessage_StoredAsNull(string? sent)
+    {
+        var documentId = Guid.NewGuid();
+        using var client = fixture.CreateClient();
+
+        using var response = await client.PostAsync(
+            $"api/documents/{documentId}/versions",
+            ApiExtensions.VersionForm(
+                TestDocx.BuildPlainDocx(), "doc.docx", Guid.NewGuid().ToString(),
+                message: sent));
+
+        Assert.Equal(HttpStatusCode.Created, response.StatusCode);
+
+        await using var db = fixture.CreateDb();
+        var version = await db.DocumentVersions.AsNoTracking().SingleAsync(v => v.DocumentId == documentId);
+        Assert.Null(version.Message);
+
+        using var history = await client.GetAsync($"api/documents/{documentId}/versions");
+        var items = await history.Content.ReadFromJsonAsync<List<VersionItem>>(IntegrationTestFixture.Json);
+        Assert.Null(items!.Single().Message);
+    }
+
+    [Fact]
+    public async Task Upload_TrimsSurroundingWhitespace()
+    {
+        var documentId = Guid.NewGuid();
+        using var client = fixture.CreateClient();
+
+        using var response = await client.PostAsync(
+            $"api/documents/{documentId}/versions",
+            ApiExtensions.VersionForm(
+                TestDocx.BuildPlainDocx(), "doc.docx", Guid.NewGuid().ToString(),
+                message: "  แก้ไขข้อ 3  "));
+
+        Assert.Equal(HttpStatusCode.Created, response.StatusCode);
+
+        await using var db = fixture.CreateDb();
+        var version = await db.DocumentVersions.AsNoTracking().SingleAsync(v => v.DocumentId == documentId);
+        Assert.Equal("แก้ไขข้อ 3", version.Message);
+    }
+
+    [Fact]
+    public async Task Upload_OversizeMessage_Returns400_NoSideEffect()
+    {
+        var documentId = Guid.NewGuid();
+        using var client = fixture.CreateClient();
+
+        using var response = await client.PostAsync(
+            $"api/documents/{documentId}/versions",
+            ApiExtensions.VersionForm(
+                TestDocx.BuildPlainDocx(), "doc.docx", Guid.NewGuid().ToString(),
+                message: new string('ก', 2049)));
+
+        Assert.Equal(HttpStatusCode.BadRequest, response.StatusCode);
+
+        await using var db = fixture.CreateDb();
+        Assert.False(await db.Documents.AsNoTracking().AnyAsync(d => d.Id == documentId)); // ไม่มี side effect
+    }
+
+    [Fact]
+    public async Task Upload_MessageExactly2048_Succeeds()
+    {
+        var documentId = Guid.NewGuid();
+        using var client = fixture.CreateClient();
+        var message = new string('ก', 2048);
+
+        using var response = await client.PostAsync(
+            $"api/documents/{documentId}/versions",
+            ApiExtensions.VersionForm(
+                TestDocx.BuildPlainDocx(), "doc.docx", Guid.NewGuid().ToString(),
+                message: message));
+
+        Assert.Equal(HttpStatusCode.Created, response.StatusCode);
+
+        await using var db = fixture.CreateDb();
+        var version = await db.DocumentVersions.AsNoTracking().SingleAsync(v => v.DocumentId == documentId);
+        Assert.Equal(message, version.Message);
+    }
+
+    [Fact]
+    public async Task SecondUpload_KeepsPerVersionMessages()
+    {
+        var documentId = Guid.NewGuid();
+        using var client = fixture.CreateClient();
+
+        using var first = await client.PostAsync(
+            $"api/documents/{documentId}/versions",
+            ApiExtensions.VersionForm(
+                TestDocx.BuildPlainDocx("v1"), "doc.docx", Guid.NewGuid().ToString(),
+                message: "ฉบับแรก"));
+        using var second = await client.PostAsync(
+            $"api/documents/{documentId}/versions",
+            ApiExtensions.VersionForm(
+                TestDocx.BuildPlainDocx("v2"), "doc.docx", Guid.NewGuid().ToString(),
+                message: "แก้ไขเงินเดือน"));
+
+        Assert.Equal(HttpStatusCode.Created, second.StatusCode);
+
+        // history ใหม่ → เก่า พร้อม message ของแต่ละ version เป็นของตัวเอง
+        using var history = await client.GetAsync($"api/documents/{documentId}/versions");
+        var items = await history.Content.ReadFromJsonAsync<List<VersionItem>>(IntegrationTestFixture.Json);
+        Assert.Equal(2, items!.Count);
+        Assert.Equal(2, items[0].VersionNumber);
+        Assert.Equal("แก้ไขเงินเดือน", items[0].Message);
+        Assert.Equal(1, items[1].VersionNumber);
+        Assert.Equal("ฉบับแรก", items[1].Message);
+    }
+
+    [Fact]
+    public async Task Generate_WithMessage_CreatesV1WithMessage()
+    {
+        using var client = fixture.CreateClient();
+        var (templateId, _) = await TestFlow.CreateConfiguredTemplateAsync(client, "msg-gen");
+
+        var generated = await TestFlow.GenerateDocumentAsync(
+            client, templateId, TestFlow.DefaultValues, message: "ฉบับเสนอลงนามครั้งแรก");
+
+        await using var db = fixture.CreateDb();
+        var version = await db.DocumentVersions.AsNoTracking()
+            .SingleAsync(v => v.DocumentId == generated.DocumentId);
+        Assert.Equal(1, version.VersionNumber);
+        Assert.Equal("ฉบับเสนอลงนามครั้งแรก", version.Message);
+
+        using var history = await client.GetAsync($"api/documents/{generated.DocumentId}/versions");
+        var items = await history.Content.ReadFromJsonAsync<List<VersionItem>>(IntegrationTestFixture.Json);
+        Assert.Equal("ฉบับเสนอลงนามครั้งแรก", items!.Single().Message);
+    }
+
+    /// <summary>400 ต้องเกิดก่อนแตะ MinIO/template — ไม่ทิ้ง orphan object ใน bucket</summary>
+    [Fact]
+    public async Task Generate_OversizeMessage_Returns400()
+    {
+        using var client = fixture.CreateClient();
+        var (templateId, _) = await TestFlow.CreateConfiguredTemplateAsync(client, "msg-gen-oversize");
+
+        using var response = await client.PostAsJsonAsync(
+            "api/documents/generate",
+            new { templateId, values = TestFlow.DefaultValues, message = new string('ก', 2049) },
+            IntegrationTestFixture.Json);
+
+        Assert.Equal(HttpStatusCode.BadRequest, response.StatusCode);
+    }
+}

backend/WordVersioning.Api/Controllers/DocumentsController.cs

@@ -34,6 +34,7 @@ public class DocumentsController(
 
     private const long MaxUploadBytes = 100L * 1024 * 1024; // 100MB ตาม spec
     private const int MaxVersionInsertRetries = 5;
+    private const int MaxVersionMessageLength = 2048; // FR-13 — ตรงกับ HasMaxLength ใน AppDbContext
 
     /// <summary>FR-5 — อัปโหลด version ใหม่ (auto-create Document ถ้ายังไม่มี)
     /// + FR-11: แนบ `fields` (map tag→text) → sync latest values + snapshot ต่อ version</summary>
@@ -59,6 +60,11 @@ public class DocumentsController(
         if (!FieldMapJson.TryParse(request.Fields, out var fieldMap, out var fieldsError))
             return BadRequest(fieldsError);
 
+        // FR-13 — commit message ทางเลือก (เช็คก่อนแตะ DB/storage กัน 500 จากข้อจำกัดความยาว)
+        var message = NormalizeMessage(request.Message);
+        if (message is { Length: > MaxVersionMessageLength })
+            return BadRequest($"`message` ยาวเกิน {MaxVersionMessageLength} อักขระ");
+
         var now = DateTimeOffset.UtcNow;
         var fileName = request.File.FileName;
 
@@ -131,6 +137,7 @@ public class DocumentsController(
                 CreatedByUserId = currentUser.UserId, // จาก claim `sub` เท่านั้น
                 CreatedAt = now,
                 FieldsSnapshotJson = fieldsSnapshotJson,
+                Message = message, // FR-13
             };
             db.DocumentVersions.Add(version);
 
@@ -212,6 +219,11 @@ public class DocumentsController(
         if (!FieldMapJson.TryNormalize(request.Values, out var values, out var valuesError))
             return BadRequest($"`values` ผิด format: {valuesError}");
 
+        // FR-13 — เช็คก่อนทำ MinIO/template IO ใดๆ (กัน 500 + orphan object ใน bucket เมื่อ DB reject ทีหลัง)
+        var message = NormalizeMessage(request.Message);
+        if (message is { Length: > MaxVersionMessageLength })
+            return BadRequest($"`message` ยาวเกิน {MaxVersionMessageLength} อักขระ");
+
         // validate required + type (FR-10) — field ที่ส่งเกินนิยาม ignore ตาม policy เดียวกับ FR-11
         var missingRequired = fieldDefs
             .Where(f => f.IsRequired && (!values.TryGetValue(f.Key, out var v) || string.IsNullOrWhiteSpace(v ?? string.Empty)))
@@ -297,6 +309,7 @@ public class DocumentsController(
                 ContentHash = contentHash,
                 CreatedByUserId = currentUser.UserId,
                 CreatedAt = now,
+                Message = message, // FR-13
             };
             db.DocumentVersions.Add(version);
 
@@ -420,12 +433,13 @@ public class DocumentsController(
                 v.CreatedByUserId,
                 v.ContentHash,
                 v.FieldsSnapshotJson,
+                v.Message,
             })
             .ToListAsync(ct);
 
         return Ok(rows.Select(r => new VersionListItem(
             r.Id, r.VersionNumber, r.CreatedAt, r.CreatedByUserId, r.ContentHash,
-            ParseSnapshot(r.FieldsSnapshotJson))).ToList());
+            ParseSnapshot(r.FieldsSnapshotJson), r.Message)).ToList());
     }
 
     /// <summary>FR-7 — ดาวน์โหลด version ที่ระบุ (proxy stream จาก MinIO — ไม่ expose MinIO ตรงๆ)</summary>
@@ -535,4 +549,9 @@ public class DocumentsController(
 
     private static bool IsUniqueViolation(DbUpdateException ex) =>
         ex.InnerException is PostgresException { SqlState: PostgresErrorCodes.UniqueViolation };
+
+    /// <summary>FR-13 — normalize commit message: ว่าง/whitespace ล้วน → null, ไม่เช่นนั้น trim
+    /// (นโยบายเดียวกับ Template.Description ใน TemplatesController)</summary>
+    private static string? NormalizeMessage(string? message) =>
+        string.IsNullOrWhiteSpace(message) ? null : message.Trim();
 }

backend/WordVersioning.Api/Data/AppDbContext.cs

@@ -40,6 +40,7 @@ public class AppDbContext(DbContextOptions<AppDbContext> options) : DbContext(op
 
             entity.Property(x => x.ObjectKey).HasMaxLength(1024);
             entity.Property(x => x.ContentHash).HasMaxLength(64);
+            entity.Property(x => x.Message).HasMaxLength(2048); // FR-13 commit message — นโยบายเดียวกับ Template.Description
 
             entity.HasOne(x => x.Document)
                 .WithMany(d => d.Versions)

backend/WordVersioning.Api/Migrations/20260820144855_AddVersionMessage.Designer.cs

@@ -0,0 +1,256 @@
+// <auto-generated />
+using System;
+using Microsoft.EntityFrameworkCore;
+using Microsoft.EntityFrameworkCore.Infrastructure;
+using Microsoft.EntityFrameworkCore.Migrations;
+using Microsoft.EntityFrameworkCore.Storage.ValueConversion;
+using Npgsql.EntityFrameworkCore.PostgreSQL.Metadata;
+using WordVersioning.Api.Data;
+
+#nullable disable
+
+namespace WordVersioning.Api.Migrations
+{
+    [DbContext(typeof(AppDbContext))]
+    [Migration("20260820144855_AddVersionMessage")]
+    partial class AddVersionMessage
+    {
+        /// <inheritdoc />
+        protected override void BuildTargetModel(ModelBuilder modelBuilder)
+        {
+#pragma warning disable 612, 618
+            modelBuilder
+                .HasAnnotation("ProductVersion", "8.0.11")
+                .HasAnnotation("Relational:MaxIdentifierLength", 63);
+
+            NpgsqlModelBuilderExtensions.UseIdentityByDefaultColumns(modelBuilder);
+
+            modelBuilder.Entity("WordVersioning.Api.Models.Document", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("AddInSignature")
+                        .IsRequired()
+                        .HasMaxLength(64)
+                        .HasColumnType("character varying(64)");
+
+                    b.Property<DateTimeOffset>("CreatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("FileName")
+                        .IsRequired()
+                        .HasMaxLength(512)
+                        .HasColumnType("character varying(512)");
+
+                    b.Property<Guid?>("TemplateId")
+                        .HasColumnType("uuid");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("TemplateId");
+
+                    b.ToTable("Documents");
+                });
+
+            modelBuilder.Entity("WordVersioning.Api.Models.DocumentFieldValue", b =>
+                {
+                    b.Property<Guid>("DocumentId")
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("FieldKey")
+                        .HasMaxLength(256)
+                        .HasColumnType("character varying(256)");
+
+                    b.Property<Guid>("SourceVersionId")
+                        .HasColumnType("uuid");
+
+                    b.Property<DateTimeOffset>("UpdatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("UpdatedByUserId")
+                        .IsRequired()
+                        .HasColumnType("text");
+
+                    b.Property<string>("Value")
+                        .IsRequired()
+                        .HasColumnType("text");
+
+                    b.HasKey("DocumentId", "FieldKey");
+
+                    b.ToTable("DocumentFieldValues");
+                });
+
+            modelBuilder.Entity("WordVersioning.Api.Models.DocumentVersion", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("ContentHash")
+                        .IsRequired()
+                        .HasMaxLength(64)
+                        .HasColumnType("character varying(64)");
+
+                    b.Property<DateTimeOffset>("CreatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("CreatedByUserId")
+                        .IsRequired()
+                        .HasColumnType("text");
+
+                    b.Property<Guid>("DocumentId")
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("FieldsSnapshotJson")
+                        .HasColumnType("text");
+
+                    b.Property<string>("Message")
+                        .HasMaxLength(2048)
+                        .HasColumnType("character varying(2048)");
+
+                    b.Property<string>("ObjectKey")
+                        .IsRequired()
+                        .HasMaxLength(1024)
+                        .HasColumnType("character varying(1024)");
+
+                    b.Property<int>("VersionNumber")
+                        .HasColumnType("integer");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("DocumentId", "VersionNumber")
+                        .IsUnique();
+
+                    b.ToTable("DocumentVersions");
+                });
+
+            modelBuilder.Entity("WordVersioning.Api.Models.Template", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<DateTimeOffset>("CreatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.Property<string>("Description")
+                        .HasMaxLength(2048)
+                        .HasColumnType("character varying(2048)");
+
+                    b.Property<bool>("IsActive")
+                        .HasColumnType("boolean");
+
+                    b.Property<string>("Name")
+                        .IsRequired()
+                        .HasMaxLength(256)
+                        .HasColumnType("character varying(256)");
+
+                    b.Property<string>("ObjectKey")
+                        .IsRequired()
+                        .HasMaxLength(1024)
+                        .HasColumnType("character varying(1024)");
+
+                    b.Property<DateTimeOffset>("UpdatedAt")
+                        .HasColumnType("timestamp with time zone");
+
+                    b.HasKey("Id");
+
+                    b.ToTable("Templates");
+                });
+
+            modelBuilder.Entity("WordVersioning.Api.Models.TemplateField", b =>
+                {
+                    b.Property<Guid>("Id")
+                        .ValueGeneratedOnAdd()
+                        .HasColumnType("uuid");
+
+                    b.Property<bool>("IsRequired")
+                        .HasColumnType("boolean");
+
+                    b.Property<string>("Key")
+                        .IsRequired()
+                        .HasMaxLength(256)
+                        .HasColumnType("character varying(256)");
+
+                    b.Property<string>("Label")
+                        .IsRequired()
+                        .HasMaxLength(512)
+                        .HasColumnType("character varying(512)");
+
+                    b.Property<int>("SortOrder")
+                        .HasColumnType("integer");
+
+                    b.Property<Guid>("TemplateId")
+                        .HasColumnType("uuid");
+
+                    b.Property<string>("Type")
+                        .IsRequired()
+                        .HasMaxLength(16)
+                        .HasColumnType("character varying(16)");
+
+                    b.HasKey("Id");
+
+                    b.HasIndex("TemplateId", "Key")
+                        .IsUnique();
+
+                    b.ToTable("TemplateFields");
+                });
+
+            modelBuilder.Entity("WordVersioning.Api.Models.Document", b =>
+                {
+                    b.HasOne("WordVersioning.Api.Models.Template", "Template")
+                        .WithMany("Documents")
+                        .HasForeignKey("TemplateId")
+                        .OnDelete(DeleteBehavior.Restrict);
+
+                    b.Navigation("Template");
+                });
+
+            modelBuilder.Entity("WordVersioning.Api.Models.DocumentFieldValue", b =>
+                {
+                    b.HasOne("WordVersioning.Api.Models.Document", null)
+                        .WithMany()
+                        .HasForeignKey("DocumentId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+                });
+
+            modelBuilder.Entity("WordVersioning.Api.Models.DocumentVersion", b =>
+                {
+                    b.HasOne("WordVersioning.Api.Models.Document", "Document")
+                        .WithMany("Versions")
+                        .HasForeignKey("DocumentId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("Document");
+                });
+
+            modelBuilder.Entity("WordVersioning.Api.Models.TemplateField", b =>
+                {
+                    b.HasOne("WordVersioning.Api.Models.Template", "Template")
+                        .WithMany("Fields")
+                        .HasForeignKey("TemplateId")
+                        .OnDelete(DeleteBehavior.Cascade)
+                        .IsRequired();
+
+                    b.Navigation("Template");
+                });
+
+            modelBuilder.Entity("WordVersioning.Api.Models.Document", b =>
+                {
+                    b.Navigation("Versions");
+                });
+
+            modelBuilder.Entity("WordVersioning.Api.Models.Template", b =>
+                {
+                    b.Navigation("Documents");
+
+                    b.Navigation("Fields");
+                });
+#pragma warning restore 612, 618
+        }
+    }
+}

backend/WordVersioning.Api/Migrations/20260820144855_AddVersionMessage.cs

@@ -0,0 +1,29 @@
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace WordVersioning.Api.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddVersionMessage : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<string>(
+                name: "Message",
+                table: "DocumentVersions",
+                type: "character varying(2048)",
+                maxLength: 2048,
+                nullable: true);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropColumn(
+                name: "Message",
+                table: "DocumentVersions");
+        }
+    }
+}

backend/WordVersioning.Api/Migrations/AppDbContextModelSnapshot.cs

@@ -103,6 +103,10 @@ namespace WordVersioning.Api.Migrations
                     b.Property<string>("FieldsSnapshotJson")
                         .HasColumnType("text");
 
+                    b.Property<string>("Message")
+                        .HasMaxLength(2048)
+                        .HasColumnType("character varying(2048)");
+
                     b.Property<string>("ObjectKey")
                         .IsRequired()
                         .HasMaxLength(1024)

backend/WordVersioning.Api/Models/DocumentVersion.cs

@@ -25,4 +25,7 @@ public class DocumentVersion
 
     /// <summary>Snapshot ค่า fields ของ version นี้ (FR-11) — map tag→text แบบ JSON</summary>
     public string? FieldsSnapshotJson { get; set; }
+
+    /// <summary>คำอธิบาย version จากผู้ใช้ แบบ git commit message (FR-13) — optional ยาวสูงสุด 2048</summary>
+    public string? Message { get; set; }
 }

backend/WordVersioning.Api/Models/VersionDtos.cs

@@ -15,6 +15,9 @@ public class UploadVersionRequest
 
     /// <summary>JSON object map tag→text จาก content controls (FR-11)</summary>
     public string? Fields { get; set; }
+
+    /// <summary>คำอธิบาย version แบบ commit message (FR-13) — optional</summary>
+    public string? Message { get; set; }
 }
 
 public record UploadVersionResponse(Guid VersionId, int VersionNumber);
@@ -27,18 +30,22 @@ public class GenerateDocumentRequest
 
     /// <summary>map fieldKey → value (ค่า scalar ทั้งหมด)</summary>
     public JsonElement Values { get; set; }
+
+    /// <summary>คำอธิบาย version แบบ commit message (FR-13) — optional</summary>
+    public string? Message { get; set; }
 }
 
 public record GenerateDocumentResponse(Guid DocumentId, Guid VersionId, int VersionNumber, string DownloadUrl);
 
-/// <summary>item ของ version history — fields คือ snapshot ที่ parse แล้ว (ถ้ามี)</summary>
+/// <summary>item ของ version history — fields คือ snapshot ที่ parse แล้ว (ถ้ามี), message คือคำอธิบายของผู้ใช้ (FR-13)</summary>
 public record VersionListItem(
     Guid VersionId,
     int VersionNumber,
     DateTimeOffset CreatedAt,
     string CreatedByUserId,
     string ContentHash,
-    object? Fields);
+    object? Fields,
+    string? Message);
 
 /// <summary>response ของ GET .../download-link — presigned URL อายุสั้นให้เปิดในเบราว์เซอร์ของผู้ใช้</summary>
 public record VersionDownloadLinkResponse(string Url, DateTimeOffset ExpiresAt);