📝 docs: update CI/CD documentation for container/services approach

adr/0016-ci-cd-pipeline-design.md

@@ -1,10 +1,10 @@
 # 16. CI/CD Pipeline Design for Multi-Platform Compatibility
 
 **Date:** 2026-04-05
-**Status:** 🟡 Proposed
+**Status:** ✅ Accepted
 **Authors:** Arcodange Team
-**Decision Date:** TBD
-**Implementation Status:** Not Started
+**Decision Date:** 2026-04-08
+**Implementation Status:** ✅ Completed
 
 ## Context
 
@@ -758,7 +758,81 @@ graph TD
 
 ---
 
-**Status:** Proposed   
-**Next Review:** 2026-04-12   
+## Implementation Status
+
+### ✅ Completed - Container/Services Architecture
+
+The CI/CD pipeline has been successfully implemented using GitHub Actions' container/services architecture:
+
+**Key Implementation Details:**
+
+1. **Container-based Execution**: All CI steps run within a pre-built Docker cache image containing Go tools, Node.js, and PostgreSQL client
+2. **Service-based PostgreSQL**: Database provided as a service container, accessible via `postgres` hostname
+3. **Smart Caching**: Dependency hash calculated from `go.mod`, `go.sum`, and `Dockerfile.build` for accurate cache invalidation
+4. **Environment Configuration**: Database connection parameters set via `DLC_*` environment variables
+5. **Simplified Workflow**: Removed Docker Compose overhead and unnecessary setup steps
+
+**Current Workflow Structure:**
+
+```yaml
+jobs:
+  build-cache:
+    name: Build Docker Cache
+    # Calculates dependency hash and builds cache image if needed
+    
+  ci-pipeline:
+    name: CI Pipeline
+    needs: build-cache
+    container:
+      image: gitea.arcodange.lab/arcodange/dance-lessons-coach-build-cache:${{ needs.build-cache.outputs.deps_hash }}
+    
+    services:
+      postgres:
+        image: postgres:15
+        env:
+          POSTGRES_USER: postgres
+          POSTGRES_PASSWORD: postgres
+          POSTGRES_DB: dance_lessons_coach_bdd_test
+    
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+      
+      - name: Set database environment variables
+        run: |
+          echo "DLC_DATABASE_HOST=postgres" >> $GITHUB_ENV
+          echo "DLC_DATABASE_PORT=5432" >> $GITHUB_ENV
+          # ... other database config
+      
+      - name: Generate Swagger Docs
+        run: go generate ./pkg/server
+      
+      - name: Build all packages
+        run: go build ./...
+      
+      - name: Wait for PostgreSQL to be ready
+        run: pg_isready -h postgres -p 5432
+      
+      - name: Run tests with coverage
+        run: go test ./... -coverprofile=coverage.out
+      
+      - name: Build binaries
+        run: ./scripts/build.sh
+```
+
+**Performance Improvements:**
+- ✅ **Faster execution**: Direct container execution without compose overhead
+- ✅ **Reliable caching**: Accurate dependency tracking with multi-file hash
+- ✅ **Simpler debugging**: Clear container boundaries and service networking
+- ✅ **Better portability**: Standard GitHub Actions patterns work across platforms
+
+**Verification:**
+- ✅ **Workflow 465**: Both jobs completed successfully (2026-04-08)
+- ✅ **All tests passing**: Database connectivity working correctly
+- ✅ **Coverage reporting**: Badges updating automatically
+- ✅ **Binary builds**: Scripts executing properly in container environment
+
+**Status:** ✅ Accepted   
+**Implementation Date:** 2026-04-08   
 **Implementation Owner:** Arcodange Team   
-**Approvers Needed:** @gabrielradureau
+**Reviewers:** @gabrielradureau