feat: add actions/cache and Docker layer caching

- actions/cache@v4 for node_modules across unit-tests and build jobs
- Manual sha256sum key since Gitea lacks hashFiles() support
- Docker BuildKit registry-based cache layers (--cache-from/--cache-to)
- Both runners configured with their own cache server ports

.gitea/workflows/pr.yml

@@ -22,6 +22,21 @@ jobs:
       - name: Checkout code
         uses: actions/checkout@v4
 
+      - name: Compute dependency cache key
+        id: npm-key
+        run: |
+          echo "hash=$(sha256sum package-lock.json | cut -d' ' -f1)" >> $GITHUB_OUTPUT
+
+      - name: Cache node_modules
+        uses: actions/cache@v4
+        with:
+          path: |
+            node_modules
+            ~/.npm
+          key: npm-${{ runner.os }}-${{ steps.npm-key.outputs.hash }}
+          restore-keys: |
+            npm-${{ runner.os }}-
+
       - name: Install dependencies
         run: npm ci --legacy-peer-deps
 
@@ -46,6 +61,21 @@ jobs:
 
       # Required for acceptance tests - they import prisma via @/ path alias
       # and @cucumber/cucumber for cucumber-e2e tests
+      - name: Compute dependency cache key
+        id: npm-key
+        run: |
+          echo "hash=$(sha256sum package-lock.json | cut -d' ' -f1)" >> $GITHUB_OUTPUT
+
+      - name: Cache node_modules
+        uses: actions/cache@v4
+        with:
+          path: |
+            node_modules
+            ~/.npm
+          key: npm-${{ runner.os }}-${{ steps.npm-key.outputs.hash }}
+          restore-keys: |
+            npm-${{ runner.os }}-
+
       - name: Install dependencies
         run: npm ci --legacy-peer-deps
 
@@ -60,11 +90,19 @@ jobs:
           echo "pr_number=$(echo $GITHUB_REF | grep -oP 'refs/pull/\K[0-9]+')" >> $GITHUB_OUTPUT
           echo "short_sha=$(echo $GITHUB_SHA | cut -c1-7)" >> $GITHUB_OUTPUT
 
+      - name: Login to Registry
+        run: |
+          docker login ${{ env.REGISTRY }} -u ${{ secrets.DOCKER_LOGIN }} -p ${{ secrets.DOCKER_PASSWORD }}
+
       - name: Build Docker image for PR
+        env:
+          DOCKER_BUILDKIT: 1
         run: |
           IMAGE_TAG="pr-${{ steps.info.outputs.pr_number }}-${{ steps.info.outputs.short_sha }}"
           docker build \
             --target runner \
+            --cache-from type=registry,ref=${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:cache \
+            --cache-to type=registry,ref=${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:cache,mode=max \
             --build-arg GIT_COMMIT=$GITHUB_SHA \
             -t ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:${IMAGE_TAG} \
             .

.gitea/workflows/release.yml

@@ -109,9 +109,13 @@ jobs:
 
       - name: Build test-capable image
         if: steps.commit.outputs.committed == 'true'
+        env:
+          DOCKER_BUILDKIT: 1
         run: |
           docker build \
             --target test-runner \
+            --cache-from type=registry,ref=${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:cache-test \
+            --cache-to type=registry,ref=${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:cache-test,mode=max \
             --build-arg GIT_COMMIT=${{ github.sha }} \
             -t ${{ env.IMAGE_NAME }}-test:${{ steps.version.outputs.new_version }} \
             .
@@ -127,9 +131,13 @@ jobs:
 
       - name: Build production image
         if: steps.commit.outputs.committed == 'true'
+        env:
+          DOCKER_BUILDKIT: 1
         run: |
           docker build \
             --target runner \
+            --cache-from type=registry,ref=${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:cache \
+            --cache-to type=registry,ref=${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:cache,mode=max \
             --build-arg GIT_COMMIT=${{ github.sha }} \
             -t ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:${{ steps.version.outputs.new_version }} \
             -t ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}:latest \