feat: add lint and build GitHub Actions for pull requests

.github/workflows/build.yml

@@ -0,0 +1,59 @@
+name: Build
+
+on:
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4.2.2
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4.1.0
+        with:
+          node-version: '24.8.0'
+
+      - name: Install pnpm
+        uses: pnpm/action-setup@v4.0.0
+        with:
+          version: 9.0.0
+
+      - name: Get pnpm store directory
+        id: pnpm-cache
+        shell: bash
+        run: |
+          echo "STORE_PATH=$(pnpm store path)" >> $GITHUB_OUTPUT
+
+      - name: Setup pnpm cache
+        uses: actions/cache@v4
+        with:
+          path: ${{ steps.pnpm-cache.outputs.STORE_PATH }}
+          key: ${{ runner.os }}-pnpm-store-${{ hashFiles('**/pnpm-lock.yaml') }}
+          restore-keys: |
+            ${{ runner.os }}-pnpm-store-
+
+      - name: Install dependencies
+        run: pnpm install
+
+      - name: Generate Prisma client
+        run: pnpm --filter @repo/db generate
+
+      - name: Build web app
+        run: pnpm --filter web build
+        env:
+          # CI-only placeholder values for build testing.
+          # These values are only used to satisfy build-time validation in CI and are not used for runtime operations or actual connections.
+          # They are not real credentials and are safe for public repositories.
+          DATABASE_URL: postgresql://user:password@localhost:5432/test
+          REDIS_HOST: localhost
+          REDIS_PORT: 6379
+          REDIS_PASSWORD: testpassword
+          BETTER_AUTH_SECRET: ci_test_secret_change_me
+          BETTER_AUTH_URL: http://localhost:3000
+          ENCRYPTION_SECRET: ci_encryption_secret_change_me

.github/workflows/lint.yml

@@ -0,0 +1,45 @@
+name: Lint
+
+on:
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4.2.2
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4.1.0
+        with:
+          node-version: '24.8.0'
+
+      - name: Install pnpm
+        uses: pnpm/action-setup@v4.0.0
+        with:
+          version: 9.0.0
+
+      - name: Get pnpm store directory
+        id: pnpm-cache
+        shell: bash
+        run: |
+          echo "STORE_PATH=$(pnpm store path)" >> $GITHUB_OUTPUT
+
+      - name: Setup pnpm cache
+        uses: actions/cache@v4
+        with:
+          path: ${{ steps.pnpm-cache.outputs.STORE_PATH }}
+          key: ${{ runner.os }}-pnpm-store-${{ hashFiles('**/pnpm-lock.yaml') }}
+          restore-keys: |
+            ${{ runner.os }}-pnpm-store-
+
+      - name: Install dependencies
+        run: pnpm install
+
+      - name: Run lint
+        run: pnpm lint