chore(root): scaffold monorepo — Phase 0 complete

.github/workflows/ci.yml

@@ -0,0 +1,64 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+jobs:
+  check:
+    name: Typecheck, Lint, Test
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: oven-sh/setup-bun@v2
+        with:
+          bun-version: latest
+      - name: Cache bun dependencies
+        uses: actions/cache@v4
+        with:
+          path: ~/.bun/install/cache
+          key: ${{ runner.os }}-bun-${{ hashFiles('**/bun.lock') }}
+          restore-keys: |
+            ${{ runner.os }}-bun-
+      - name: Install dependencies
+        run: bun install --frozen-lockfile
+      - name: Typecheck
+        run: bun run typecheck
+      - name: Lint
+        run: bun run lint
+      - name: Test with coverage
+        run: bun run test:coverage
+
+  build:
+    name: Build packages
+    runs-on: ubuntu-latest
+    needs: check
+    steps:
+      - uses: actions/checkout@v4
+      - uses: oven-sh/setup-bun@v2
+        with:
+          bun-version: latest
+      - name: Install dependencies
+        run: bun install --frozen-lockfile
+      - name: Build
+        run: bun run build
+
+  audit:
+    name: Security audit
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: oven-sh/setup-bun@v2
+        with:
+          bun-version: latest
+      - name: Install dependencies
+        run: bun install --frozen-lockfile
+      - name: Audit
+        run: bun audit || true
+
+  # e2e:
+  #   name: E2E (Playwright)
+  #   runs-on: ubuntu-latest
+  #   # Enabled in Phase 3 when chess UI exists