ci: add pull request quality gates

Co-Authored-By: gpt-5.6-terra <noreply@openai.com>

.gitea/actions/setup/action.yml

@@ -0,0 +1,9 @@
+name: Setup
+description: Set up the Node version required by this repository. Requires actions/checkout to have already run.
+
+runs:
+  using: composite
+  steps:
+    - uses: actions/setup-node@v4
+      with:
+        node-version-file: .node-version

.gitea/workflows/ci.yml

@@ -0,0 +1,124 @@
+name: CI
+
+on:
+  pull_request:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  install-and-build:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: ./.gitea/actions/setup
+
+      - name: Clean install dependencies
+        run: npm ci
+
+      - name: Production build
+        run: npm run build
+
+      - name: Archive dependencies
+        run: tar -czf node_modules.tar.gz node_modules
+
+      - uses: actions/upload-artifact@v3
+        with:
+          name: node_modules-${{ github.run_id }}
+          path: node_modules.tar.gz
+
+      - name: Archive build artifacts
+        run: tar -czf build-artifacts.tar.gz dist
+
+      - uses: actions/upload-artifact@v3
+        with:
+          name: build-artifacts-${{ github.run_id }}
+          path: build-artifacts.tar.gz
+
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: ./.gitea/actions/setup
+
+      - name: Clean install dependencies
+        run: npm ci
+
+      - name: Lint
+        run: npm run lint
+
+  format:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: ./.gitea/actions/setup
+
+      - name: Clean install dependencies
+        run: npm ci
+
+      - name: Check formatting
+        run: npm run format:check
+
+  typecheck-source:
+    runs-on: ubuntu-latest
+    needs: install-and-build
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: ./.gitea/actions/setup
+
+      - uses: actions/download-artifact@v3
+        with:
+          name: node_modules-${{ github.run_id }}
+
+      - uses: actions/download-artifact@v3
+        with:
+          name: build-artifacts-${{ github.run_id }}
+
+      - name: Restore dependencies and build artifacts
+        run: |
+          tar -xzf node_modules.tar.gz
+          tar -xzf build-artifacts.tar.gz
+
+      - name: Typecheck source
+        run: npm run typecheck
+
+  typecheck-tests:
+    runs-on: ubuntu-latest
+    needs: install-and-build
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: ./.gitea/actions/setup
+
+      - uses: actions/download-artifact@v3
+        with:
+          name: node_modules-${{ github.run_id }}
+
+      - name: Restore dependencies
+        run: tar -xzf node_modules.tar.gz
+
+      - name: Typecheck tests
+        run: npm run typecheck:test
+
+  test:
+    runs-on: ubuntu-latest
+    needs: install-and-build
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: ./.gitea/actions/setup
+
+      - uses: actions/download-artifact@v3
+        with:
+          name: node_modules-${{ github.run_id }}
+
+      - name: Restore dependencies
+        run: tar -xzf node_modules.tar.gz
+
+      - name: Run full test suite
+        run: npm test