ci: faster pipelines with checks-only ci and registry build cache

Drop duplicate Next.js builds from CI, skip release commits, and cancel stale runs.

Cache pnpm on runners and use buildx registry cache for releases.

.gitea/workflows/ci.yml

@@ -11,8 +11,13 @@ on:
       - "**/*.md"
       - "docs/**"
 
+concurrency:
+  group: ci-${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
 jobs:
   checks:
+    if: "github.event_name == 'pull_request' || !startsWith(github.event.head_commit.message, 'chore: release')"
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v4
@@ -21,6 +26,8 @@ jobs:
         run: |
           corepack enable
           corepack prepare pnpm@10.33.3 --activate
+          mkdir -p /pnpm-store
+          pnpm config set store-dir /pnpm-store
 
       - name: Install dependencies
         run: pnpm install --frozen-lockfile
@@ -33,23 +40,3 @@ jobs:
 
       - name: Format check
         run: pnpm format:check
-
-  build:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4
-
-      - name: Enable pnpm
-        run: |
-          corepack enable
-          corepack prepare pnpm@10.33.3 --activate
-
-      - name: Install dependencies
-        run: pnpm install --frozen-lockfile
-
-      - name: Build
-        run: pnpm build
-        env:
-          DATABASE_URL: postgres://ci_user:ci_password@localhost:5432/ci_database
-          AUTH_SECRET: ci-auth-secret-for-build
-          NEXT_PUBLIC_APP_URL: http://localhost:3000