Build optimization: pre-built PM3 binaries, ARM64 CI, base image caching

Replace PM3 compile-from-source in pi-gen with pre-built tarball extraction
(saves 43-58 min). Merge stagePM3 into stageDangerousPi as 02-pm3-install
substage, renumber all subsequent substages. Switch CI PM3 build to native
ARM64 runner (ubuntu-24.04-arm64) eliminating QEMU overhead. Add weekly
base-image workflow for pre-baking stages 0-2. Support PM3_TARBALL,
BASE_IMAGE, and APT_PROXY env vars in build-image.sh.

Also includes prior Phase 5 work: theme system, design system integration,
component update system, OS updates, CI build pipeline, and test results.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

.github/workflows/build-release.yml

@@ -0,0 +1,152 @@
+name: Build and Release Components
+
+on:
+  push:
+    tags: ['v*']
+  workflow_dispatch:
+    inputs:
+      components:
+        description: 'Components to build (comma-separated, or "all")'
+        required: false
+        default: 'all'
+
+permissions:
+  contents: write
+
+jobs:
+  # ------------------------------------------------------------------
+  # PM3: compile natively on ARM64 runner (no QEMU overhead)
+  # ------------------------------------------------------------------
+  build-pm3:
+    runs-on: ubuntu-24.04-arm64
+    strategy:
+      matrix:
+        python_version: ['3.11', '3.12']
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Build PM3 natively on aarch64
+        env:
+          PYTHON_VERSION: ${{ matrix.python_version }}
+        run: |
+          docker run --rm \
+            -v "${GITHUB_WORKSPACE}:/workspace" \
+            -e "PYTHON_VERSION=${PYTHON_VERSION}" \
+            -e OUTPUT_DIR=/workspace/dist \
+            -w /workspace \
+            debian:trixie \
+            bash ci/build-pm3.sh
+
+      - uses: actions/upload-artifact@v4
+        with:
+          name: pm3-cp${{ matrix.python_version }}
+          path: dist/pm3-*.tar.gz
+
+  # ------------------------------------------------------------------
+  # Frontend: build Remix app
+  # ------------------------------------------------------------------
+  build-frontend:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '18'
+
+      - name: Build frontend
+        env:
+          REF_NAME: ${{ github.ref_name }}
+        run: |
+          chmod +x ci/build-frontend.sh
+          VERSION="${REF_NAME#v}" ci/build-frontend.sh
+
+      - uses: actions/upload-artifact@v4
+        with:
+          name: frontend
+          path: dist/frontend-*.tar.gz
+
+  # ------------------------------------------------------------------
+  # Backend: package Python source
+  # ------------------------------------------------------------------
+  build-backend:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Package backend
+        env:
+          REF_NAME: ${{ github.ref_name }}
+        run: |
+          chmod +x ci/build-backend.sh
+          VERSION="${REF_NAME#v}" ci/build-backend.sh
+
+      - uses: actions/upload-artifact@v4
+        with:
+          name: backend
+          path: dist/backend-*.tar.gz
+
+  # ------------------------------------------------------------------
+  # Theme: build token CSS from design system
+  # ------------------------------------------------------------------
+  build-theme:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Checkout design system
+        uses: actions/checkout@v4
+        with:
+          repository: dangerous-tacos/dt-design-system
+          path: dt-design-system
+
+      - uses: actions/setup-node@v4
+        with:
+          node-version: '18'
+
+      - name: Build theme
+        env:
+          REF_NAME: ${{ github.ref_name }}
+        run: |
+          chmod +x ci/build-theme.sh
+          VERSION="${REF_NAME#v}" \
+          DESIGN_SYSTEM_DIR="${GITHUB_WORKSPACE}/dt-design-system" \
+          ci/build-theme.sh
+
+      - uses: actions/upload-artifact@v4
+        with:
+          name: theme
+          path: dist/theme-*.tar.gz
+
+  # ------------------------------------------------------------------
+  # Create release with all component assets
+  # ------------------------------------------------------------------
+  create-release:
+    needs: [build-pm3, build-frontend, build-backend, build-theme]
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: actions/setup-python@v5
+        with:
+          python-version: '3.12'
+
+      - uses: actions/download-artifact@v4
+        with:
+          path: dist/
+          merge-multiple: true
+
+      - name: Generate release manifest
+        env:
+          REF_NAME: ${{ github.ref_name }}
+        run: |
+          python3 ci/generate-manifest.py dist/ \
+            --version "${REF_NAME#v}"
+
+      - name: Create GitHub Release
+        uses: softprops/action-gh-release@v2
+        with:
+          files: |
+            dist/*.tar.gz
+            dist/release-manifest.json
+          generate_release_notes: true