feat: convert workflows to tag-based deployment with semantic versioning

- Replace branch triggers with tag triggers for all services
- Backend: backend-dev-v1.0.0
- Learner: learner-dev-v1.0.0
- Management: management-dev-v1.0.0
- Extract version from tags and use for Docker image tagging
- Update compose.yaml to use GITEA_INSTANCE variable
- Add comprehensive deployment guide (DEPLOYMENT.md)
- Support pre-release tags (beta, rc, alpha)

BREAKING CHANGE: Pushing to dev branch no longer triggers deployment.
Must create and push version tags to deploy.

compose.yaml

@@ -5,23 +5,27 @@ services:
 
   # Backend API
   backend:
-    image: 192.168.1.60/chamomind/elearning-backend:${BACKEND_TAG:-latest}
+    image: ${GITEA_INSTANCE}/chamomind/elearning-backend:${BACKEND_TAG}
     container_name: elearning-backend
     restart: unless-stopped
     ports:
-      - "4000:4000"
+      - "20901:4000"
     env_file:
       - .env
+    environment:
+      - NODE_ENV=production
     networks:
       - elearning-shared
 
   # Frontend Learner
-  frontend-learner:
-    image: 192.168.1.60/chamomind/elearning-learner:${FRONTEND_TAG:-latest}
+  learner:
+    image: ${GITEA_INSTANCE}/chamomind/elearning-learner:${FRONTEND_TAG}
     container_name: elearning-learner
     restart: unless-stopped
     ports:
       - "20902:3000"
+    environment:
+      - PORT=${PORT_MANG:-3000}
     env_file:
       - .env
     depends_on:
@@ -30,12 +34,14 @@ services:
       - elearning-shared
 
   # Frontend Management
-  frontend-management:
-    image: 192.168.1.60/chamomind/elearning-management:${MANAGEMENT_TAG:-latest}
+  management:
+    image: ${GITEA_INSTANCE}/chamomind/elearning-management:${MANAGEMENT_TAG}
     container_name: elearning-management
     restart: unless-stopped
     ports:
       - "20903:3001"
+    environment:
+      - PORT=${PORT_MANG:-3001}
     env_file:
       - .env
     depends_on: