🤖 feat: implement trunk-based CI/CD with local testing

- Designed trunk-based development workflow with branch protection
- Added workflow validation job to prevent main branch breaks
- Integrated act (GitHub Actions runner) for local Gitea workflow testing
- Created unified CI/CD script interface (scripts/cicd.sh)
- Added YAML lint configuration with practical limits (400 chars)
- Organized all CI/CD scripts under scripts/cicd/ directory
- Confirmed Gitea/GitHub Actions compatibility via local testing
- Updated ADR 0017 with implementation details and test results
- Enhanced documentation with local development workflow

See ADR-0017 for complete trunk-based development workflow documentation.
See ADR-0016 for CI/CD pipeline design.

.gitea/workflows/ci-cd.yaml

@@ -0,0 +1,157 @@
+---
+# DanceLessonsCoach CI/CD Pipeline for Arcodange Gitea
+# Follows Arcodange conventions from webapp workflow
+# Uses .gitea/workflows/ directory and internal registry
+
+name: DanceLessonsCoach CI/CD
+
+on:
+  workflow_dispatch: true
+  push:
+    branches:
+      - main
+      - 'ci/**'
+      - 'feature/**'
+      - 'fix/**'
+      - 'refactor/**'
+    paths-ignore:
+      - 'README.md'
+      - 'doc/**'
+      - 'adr/**'
+  pull_request:
+    branches:
+      - main
+    types: [opened, synchronize, reopened, labeled]
+
+# cancel any previously-started runs of this workflow on the same branch
+concurrency:
+  group: ${{ github.ref }}-${{ github.workflow }}
+  cancel-in-progress: true
+
+# Arcodange-specific environment variables
+env:
+  GITEA_INTERNAL: "https://gitea.arcodange.lab/"
+  GITEA_EXTERNAL: "https://gitea.arcodange.fr/"
+  GITEA_ORG: "arcodange"
+  GITEA_REPO: "DanceLessonsCoach"
+  CI_REGISTRY: "gitea.arcodange.lab"
+
+jobs:
+  build-test:
+    name: Build and Test
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Set up Go
+        uses: actions/setup-go@v4
+        with:
+          go-version: '1.26.1'
+          cache: true
+
+      - name: Install dependencies
+        run: go mod tidy
+
+      - name: Build all packages
+        run: go build ./...
+
+      - name: Run tests with coverage
+        run: go test ./... -cover -v
+
+      - name: Build binaries
+        run: ./scripts/build.sh
+
+      - name: List artifacts
+        run: ls -la bin/
+
+  lint-format:
+    name: Lint and Format
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Set up Go
+        uses: actions/setup-go@v4
+        with:
+          go-version: '1.26.1'
+
+      - name: Run go fmt
+        run: go fmt ./...
+
+      - name: Run go vet
+        run: go vet ./...
+
+      - name: Check for formatting issues
+        run: |
+          if [ -n "$(go fmt ./...)" ]; then
+            echo "❌ Formatting issues found"
+            exit 1
+          fi
+          echo "✅ Code is properly formatted"
+
+  workflow-validation:
+    name: Workflow Validation
+    runs-on: ubuntu-latest
+    if: github.event_name == 'pull_request' || contains(github.ref, 'ci/')
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Validate workflow syntax
+        run: |
+          if command -v yq >/dev/null 2>&1; then
+            yq eval '.' .gitea/workflows/ci-cd.yaml > /dev/null
+            echo "✅ Workflow YAML syntax is valid"
+          else
+            echo "⚠️  yq not installed, skipping YAML validation"
+          fi
+
+      - name: Run workflow validation script
+        run: ./scripts/cicd/validate-workflow.sh
+
+      - name: Check for breaking changes
+        if: github.event_name == 'pull_request'
+        run: |
+          echo "🔍 Checking workflow changes..."
+          changes=$(git diff origin/main -- .gitea/workflows/ci-cd.yaml | grep -q "^-")
+          if [ $changes ]; then
+            echo "⚠️  Changes detected - review recommended"
+          else
+            echo "✅ No workflow changes"
+          fi
+
+  version-check:
+    name: Version Management
+    runs-on: ubuntu-latest
+    needs: [build-test, lint-format, workflow-validation]
+    if: github.ref == 'refs/heads/main'
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+
+      - name: Show current version
+        run: |
+          source VERSION
+          echo "Version: $MAJOR.$MINOR.$PATCH${PRERELEASE:+-$PRERELEASE}"
+          echo "GITEA_REPO=$GITEA_ORG/$GITEA_REPO" >> $GITHUB_ENV
+
+      - name: Check for version bump candidates
+        run: |
+          echo "📋 Last commit analysis:"
+          git log -1 --pretty=%B | head -1
+
+          if git log -1 --pretty=%B | grep -q "^feat:"; then
+            echo "🎯 Feature commit detected - consider MINOR version bump"
+          elif git log -1 --pretty=%B | grep -q "^fix:"; then
+            echo "🐛 Fix commit detected - consider PATCH version bump"
+          elif git log -1 --pretty=%B | grep -q "BREAKING CHANGE"; then
+            echo "💥 Breaking change detected - consider MAJOR version bump"
+          else
+            echo "⏭️  No automatic version bump needed"
+          fi