feat: Add PR syntax gate workflow that fails fast on TypeScript and lint errors

.github/workflows/syntax.yml

@@ -0,0 +1,45 @@
+name: Syntax Gate
+
+on:
+  pull_request:
+    types: [opened, synchronize]
+
+concurrency:
+  group: syntax-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  syntax:
+    name: Syntax & Type Check
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+
+      - name: Cache node modules
+        id: cache-node-modules
+        uses: actions/cache@v4
+        with:
+          path: |
+            node_modules
+            ~/.npm
+          key: ${{ runner.os }}-node-modules-${{ hashFiles('package-lock.json') }}
+          restore-keys: |
+            ${{ runner.os }}-node-modules-
+
+      - name: Install dependencies
+        if: steps.cache-node-modules.outputs.cache-hit != 'true'
+        run: npm ci --prefer-offline --no-audit --legacy-peer-deps
+
+      - name: TypeScript type check
+        run: npx tsc --noEmit
+
+      - name: ESLint check (no-fix)
+        run: npx eslint . --max-warnings=0

.gitignore

@@ -85,4 +85,5 @@ GoogleService-Info.plist
 # Documentation files (except README.md)
 *.md
 !README.md
+!CONTRIBUTING.md
 !docs/**/*.md

CONTRIBUTING.md

@@ -0,0 +1,27 @@
+# Contributing to TeachLink Mobile
+
+Thank you for contributing to TeachLink Mobile!
+
+## Pull Request Guidelines
+
+Before submitting a Pull Request, please ensure that your changes pass all local lint and type checks. 
+
+### Fast-Fail Syntax Gate
+We have a dedicated **Syntax Gate** workflow (`.github/workflows/syntax.yml`) that runs on every pull request `opened` or `synchronize` event.
+- This gate checks TypeScript compiler errors (`tsc --noEmit`) and code style rules (`eslint --max-warnings=0`).
+- It is optimized to complete in **under 90 seconds** using a warm cache.
+- The syntax check is a **required check** for branch protection. Pull requests cannot be merged if it fails.
+- To avoid CI failures, you should run linting and type checking locally before pushing.
+
+### Local Quality Checks
+You can run the checks locally:
+```bash
+# Run ESLint linting
+npm run lint
+
+# Run Prettier format check
+npm run format:check
+
+# Run TypeScript type check
+npx tsc --noEmit
+```