Add copilot-setup-steps.yml workflow for Copilot Coding Agent environment preparation

.github/copilot-instructions.md

@@ -122,6 +122,19 @@ The `@storybook/mcp` package (in `packages/mcp`) is framework-agnostic:
     - `mcp-endpoint.e2e.test.ts` - MCP protocol and tool tests
     - `check-deps.e2e.test.ts` - Storybook version validation
 
+**Formatting and checks (CRITICAL):**
+
+- **ALWAYS format code after making changes**: Run `pnpm run format` before committing
+- **ALWAYS run checks after formatting**: Run `pnpm run check` to ensure all checks pass
+- **Fix any failing checks**: Analyze check results and fix issues until all checks pass
+- **This is mandatory for every commit** - formatting checks will fail in CI if not done
+- The workflow is:
+  1. Make your code changes
+  2. Run `pnpm run format` to format all files
+  3. Run `pnpm run check` to verify all checks pass
+  4. Fix any failing checks and repeat step 3 until all pass
+  5. Commit your changes
+
 **Type checking:**
 
 - All packages have TypeScript strict mode enabled

.github/workflows/copilot-setup-steps.yml

@@ -0,0 +1,37 @@
+name: 'Copilot Setup Steps'
+
+# Automatically run the setup steps when they are changed to allow for easy validation, and
+# allow manual testing through the repository's "Actions" tab
+on:
+  workflow_dispatch:
+  push:
+    paths:
+      - .github/workflows/copilot-setup-steps.yml
+  pull_request:
+    paths:
+      - .github/workflows/copilot-setup-steps.yml
+
+env:
+  TURBO_ENV_MODE: loose
+
+jobs:
+  # The job MUST be called `copilot-setup-steps` or it will not be picked up by Copilot.
+  copilot-setup-steps:
+    runs-on: ubuntu-latest
+
+    # Set the permissions to the lowest permissions possible needed for your steps.
+    # Copilot will be given its own token for its operations.
+    permissions:
+      contents: read
+
+    # You can define any steps you want, and they will run before the agent starts.
+    # If you do not check out your code, Copilot will do this for you.
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@08c6903cd8c0fde910a37f88322edcfb5dd907a8 # v5.0.0
+
+      - name: Setup Node.js and Install Dependencies
+        uses: ./.github/actions/setup-node-and-install
+
+      - name: Build packages
+        run: pnpm turbo run build