Add ESLint with CI enforcement

.github/workflows/ci.yml

@@ -1,11 +1,24 @@
-name: Dummy-CI
+name: CI
 
-on: [push]
+on:
+  push:
+    branches: [main]
+  pull_request:
 
 jobs:
-  build:
+  frontend-lint:
+    name: Frontend Lint & Typecheck
     runs-on: ubuntu-latest
+    defaults:
+      run:
+        working-directory: frontend
     steps:
-    - uses: actions/checkout@v1
-    - name: Pass
-      run: echo Success!
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: npm
+          cache-dependency-path: frontend/package-lock.json
+      - run: npm ci
+      - run: npm run lint
+      - run: npm run typecheck

README.md

@@ -42,10 +42,17 @@ make dev-backend     # Backend API on http://localhost:8000
 
 ### Testing
 ```bash
-npm run lint                # Frontend linting (in frontend directory)
+# Via Docker (recommended)
+docker compose -f docker-compose.dev.yml exec frontend npm run lint
+docker compose -f docker-compose.dev.yml exec frontend npm run typecheck
+
+# Or locally in the frontend directory
+npm run lint                # ESLint (must pass with zero errors)
 npm run typecheck           # TypeScript type checking
 ```
 
+Both checks run in CI on every push and pull request.
+
 ### Database Management
 ```bash
 make reset-db               # Drop and recreate database with fresh data

docker-README.md

@@ -130,6 +130,16 @@ ADMIN_GITHUB_TEAMS=memory-python-org
 
 **Note:** Development compose file uses port 9002 for frontend, production uses 3000.
 
+### Linting & Type Checking
+
+```bash
+# ESLint (must pass with zero errors)
+docker compose -f docker-compose.dev.yml exec frontend npm run lint
+
+# TypeScript type checking
+docker compose -f docker-compose.dev.yml exec frontend npm run typecheck
+```
+
 ### Accessing the Database
 
 ```bash