feat: add comprehensive caching to CI/CD pipeline

Optimize Gitea Actions pipeline with multi-layer caching strategy:

**Lint Job:**
- Cache Poetry installation (~/.local) - avoids reinstalling Poetry
- Cache Poetry dependencies (.venv + ~/.cache/pypoetry) - reuses installed packages
- Cache key based on poetry.lock hash for automatic invalidation on dependency changes

**Build Job:**
- Cache Docker Buildx layers (/tmp/.buildx-cache) - speeds up incremental builds
- Dual cache strategy: local filesystem + container registry
- Cache rotation to prevent unlimited growth
- Per-component cache keys for optimal reuse

**Expected Performance:**
- Lint job: ~2-3x faster after first run (skip Poetry + deps installation)
- Build job: ~3-5x faster on incremental builds (reuse Docker layers)
- First run unchanged, subsequent runs significantly faster

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

.gitea/workflows/build.yml

@@ -28,13 +28,28 @@ jobs:
         uses: actions/setup-python@v5
         with:
           python-version: ${{ env.PYTHON_VERSION }}
-          cache: 'pip'
+
+      - name: Cache Poetry installation
+        uses: actions/cache@v4
+        with:
+          path: ~/.local
+          key: poetry-${{ runner.os }}-${{ env.POETRY_VERSION }}
 
       - name: Install Poetry
         run: |
           curl -sSL https://install.python-poetry.org | python3 -
           echo "$HOME/.local/bin" >> $GITHUB_PATH
 
+      - name: Cache Poetry dependencies
+        uses: actions/cache@v4
+        with:
+          path: |
+            .venv
+            ~/.cache/pypoetry
+          key: poetry-deps-${{ runner.os }}-${{ env.PYTHON_VERSION }}-${{ hashFiles('**/poetry.lock') }}
+          restore-keys: |
+            poetry-deps-${{ runner.os }}-${{ env.PYTHON_VERSION }}-
+
       - name: Install dependencies
         run: |
           poetry config virtualenvs.in-project true
@@ -64,6 +79,17 @@ jobs:
 
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
+        with:
+          buildkitd-flags: --debug
+
+      - name: Cache Docker layers
+        uses: actions/cache@v4
+        with:
+          path: /tmp/.buildx-cache
+          key: buildx-${{ matrix.component }}-${{ github.sha }}
+          restore-keys: |
+            buildx-${{ matrix.component }}-
+            buildx-
 
       - name: Log in to Container Registry
         uses: docker/login-action@v3
@@ -90,5 +116,14 @@ jobs:
           push: true
           tags: ${{ steps.meta.outputs.tags }}
           labels: ${{ steps.meta.outputs.labels }}
-          cache-from: type=registry,ref=${{ vars.PACKAGES_REGISTRY }}/${{ env.IMAGE_NAME }}/${{ matrix.component }}:buildcache
-          cache-to: type=registry,ref=${{ vars.PACKAGES_REGISTRY }}/${{ env.IMAGE_NAME }}/${{ matrix.component }}:buildcache,mode=max
+          cache-from: |
+            type=local,src=/tmp/.buildx-cache
+            type=registry,ref=${{ vars.PACKAGES_REGISTRY }}/${{ env.IMAGE_NAME }}/${{ matrix.component }}:buildcache
+          cache-to: |
+            type=local,dest=/tmp/.buildx-cache-new,mode=max
+            type=registry,ref=${{ vars.PACKAGES_REGISTRY }}/${{ env.IMAGE_NAME }}/${{ matrix.component }}:buildcache,mode=max
+
+      - name: Rotate Docker cache
+        run: |
+          rm -rf /tmp/.buildx-cache
+          mv /tmp/.buildx-cache-new /tmp/.buildx-cache || true