Initial backup of LTP-305G matrix clock setup on matrixpi

Captures everything needed to redeploy the two-display clock (hour on I2C
0x61, minute on I2C 0x63) on a fresh Pi:

- Both systemd units (matrix0x61.service, matrix0x63.service)
- Deployed Pimoroni script tree, including the local %I (12-hour) clock
  customization
- Vendored upstream sources (ltp305-python, breakout-garden) so restore is
  fully offline-capable
- Boot config snippet enabling I2C
- install.sh that wires it all back up idempotently
- Inventory doc cross-referencing every live-system path

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

vendor/ltp305-python/.github/workflows/test.yml

@@ -0,0 +1,37 @@
+name: Python Tests
+
+on:
+  pull_request:
+  push:
+    branches:
+      - master
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    strategy:
+      matrix:
+        python: [2.7, 3.5, 3.7, 3.9]
+
+    steps:
+      - uses: actions/checkout@v2
+      - name: Set up Python ${{ matrix.python }}
+        uses: actions/setup-python@v2
+        with:
+          python-version: ${{ matrix.python }}
+      - name: Install Dependencies
+        run: |
+          python -m pip install --upgrade setuptools tox
+      - name: Run Tests
+        working-directory: library
+        run: |
+          tox -e py
+      - name: Coverage
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        working-directory: library
+        run: |
+          python -m pip install coveralls
+          coveralls --service=github
+        if: ${{ matrix.python == '3.9' }}
+