Silence render-disposed spam, unbreak bundled skills, drop board wake

Three independently ugly bugs that all fed the same log flood:

* Electron's `WebFrameMain.send` writes every "Render frame was disposed"
  to stderr via `console.error`. When the worker fans a second
  agent-event past a reloading renderer, we produced thousands of
  identical lines and stalled the main loop on stderr I/O. Added a
  `mainFrame.detached` guard so the send is short-circuited before
  Electron's own catch block fires, and installed a targeted filter in
  `suppress-warnings.ts` (now actually imported from the entry point)
  so the specific `console.error("Error sending from webFrameMain:"…)`
  noise never reaches the terminal. Any other payload still surfaces.

* `dispatchAgentMessage` accepted the human-reader sentinel as a wake
  target when an agent replied to `__board__` — `wakeAgentIfPossible`
  then called `db.getAgent("__board__")`, threw, and the dispatcher
  kept repeating on every send. Strip `HUMAN_SENDER_ID` at
  `resolveMessageWakeTargets`, and keep a defense-in-depth guard in the
  heartbeat so a stray caller (future automation fan-out) cannot
  reintroduce the crash.

* Pi's skills loader rejects any SKILL.md whose frontmatter `name`
  diverges from its parent directory. The four bundled `my-writing-style`
  copies declared `name: writing-style-skill`, so every install emitted
  a warning and dropped the skill. They also lived as orphan gitlinks
  (mode 160000 without .gitmodules), and the global `*.md` gitignore
  hid every other SKILL.md from version control. Fixed the frontmatter
  to match the dir, converted the dangling submodules to plain trees,
  and allowlisted `builtin-skills/**/*.md` so a fresh clone carries the
  catalogue instead of silently losing it.

builtin-skills/software-engineer/devops-engineer/references/github-actions.md

@@ -0,0 +1,139 @@
+# GitHub Actions Pipelines
+
+## Complete CI/CD Pipeline
+
+```yaml
+name: CI/CD Pipeline
+
+on:
+  push:
+    branches: [main, develop]
+  pull_request:
+    branches: [main]
+
+env:
+  REGISTRY: ghcr.io
+  IMAGE_NAME: ${{ github.repository }}
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '20'
+          cache: 'npm'
+      - run: npm ci
+      - run: npm test
+      - run: npm run lint
+
+  build:
+    needs: test
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+    outputs:
+      image-tag: ${{ steps.meta.outputs.tags }}
+    steps:
+      - uses: actions/checkout@v4
+      - uses: docker/setup-buildx-action@v3
+      - uses: docker/login-action@v3
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      - id: meta
+        uses: docker/metadata-action@v5
+        with:
+          images: ${{ env.REGISTRY }}/${{ env.IMAGE_NAME }}
+          tags: |
+            type=sha,prefix=
+            type=ref,event=branch
+      - uses: docker/build-push-action@v5
+        with:
+          context: .
+          push: true
+          tags: ${{ steps.meta.outputs.tags }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+
+  deploy-staging:
+    needs: build
+    if: github.ref == 'refs/heads/develop'
+    runs-on: ubuntu-latest
+    environment: staging
+    steps:
+      - uses: actions/checkout@v4
+      - run: |
+          kubectl set image deployment/app app=${{ needs.build.outputs.image-tag }}
+
+  deploy-production:
+    needs: build
+    if: github.ref == 'refs/heads/main'
+    runs-on: ubuntu-latest
+    environment: production
+    steps:
+      - uses: actions/checkout@v4
+      - run: |
+          kubectl set image deployment/app app=${{ needs.build.outputs.image-tag }}
+```
+
+## Common Workflow Patterns
+
+### Matrix Builds (Multi-version testing)
+```yaml
+jobs:
+  test:
+    strategy:
+      matrix:
+        node-version: [18, 20, 22]
+        os: [ubuntu-latest, macos-latest]
+    runs-on: ${{ matrix.os }}
+    steps:
+      - uses: actions/setup-node@v4
+        with:
+          node-version: ${{ matrix.node-version }}
+```
+
+### Reusable Workflows
+```yaml
+# .github/workflows/deploy.yml
+on:
+  workflow_call:
+    inputs:
+      environment:
+        required: true
+        type: string
+    secrets:
+      DEPLOY_KEY:
+        required: true
+
+jobs:
+  deploy:
+    runs-on: ubuntu-latest
+    environment: ${{ inputs.environment }}
+    steps:
+      - run: echo "Deploying to ${{ inputs.environment }}"
+```
+
+### Caching Dependencies
+```yaml
+- uses: actions/cache@v4
+  with:
+    path: ~/.npm
+    key: ${{ runner.os }}-node-${{ hashFiles('**/package-lock.json') }}
+    restore-keys: |
+      ${{ runner.os }}-node-
+```
+
+## Quick Reference
+
+| Action | Purpose |
+|--------|---------|
+| `actions/checkout@v4` | Clone repository |
+| `actions/setup-node@v4` | Install Node.js |
+| `docker/build-push-action@v5` | Build and push Docker image |
+| `docker/metadata-action@v5` | Generate Docker tags |
+| `actions/cache@v4` | Cache dependencies |