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>

docs/inventory.md

@@ -0,0 +1,41 @@
+# LTP-305G live-system inventory
+
+Snapshot of every LTP-305G-related path on `matrixpi` at the time this repo
+was created. Use this to spot drift if anything is changed on the live system
+without being committed back here.
+
+## Systemd units (root-owned)
+
+- `/etc/systemd/system/matrix0x61.service` — runs `clock.py hour 0x61`
+- `/etc/systemd/system/matrix0x63.service` — runs `clock.py minute 0x63`
+
+Both have `WantedBy=multi-user.target` and are `enabled`.
+
+## Deployed scripts (under `dissimulo`)
+
+- `/home/dissimulo/Pimoroni/ltp305/`
+  - `docs.html`
+  - `uninstall.sh`
+  - `examples/bargraph.py`
+  - `examples/clock.py` — **locally modified**: `"hour": "%I"` (12-hour) instead of upstream `"%H"`
+  - `examples/eyes.py`
+
+## Upstream library checkouts
+
+- `/home/dissimulo/ltp305-python/` — clone of `pimoroni/ltp305-python`, used at install time
+- `/home/dissimulo/breakout-garden/` — clone of `pimoroni/breakout-garden`, used for I2C autodetect
+
+## Installed Python package
+
+- `/usr/local/lib/python3.11/dist-packages/ltp305/__init__.py`
+- `/usr/local/lib/python3.11/dist-packages/ltp305-0.0.1.dist-info/`
+
+## Boot configuration
+
+- `/boot/firmware/config.txt` contains `dtparam=i2c_arm=on` enabling the I2C bus the modules sit on.
+
+## I2C bus state
+
+`i2cdetect` is not currently installed on this system. Once `i2c-tools` is
+installed, expect `0x61` and `0x63` to appear on bus 1 when both LTP-305G
+breakouts are connected and powered.