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>

install.sh

@@ -0,0 +1,39 @@
+#!/usr/bin/env bash
+# Restore the LTP-305G matrix clock setup on a fresh Pi.
+# Run as root (or with sudo). Idempotent.
+
+set -euo pipefail
+
+REPO_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+TARGET_USER="${TARGET_USER:-dissimulo}"
+TARGET_HOME="$(getent passwd "$TARGET_USER" | cut -d: -f6)"
+
+if [[ -z "$TARGET_HOME" ]]; then
+    echo "User '$TARGET_USER' not found. Create it first or set TARGET_USER." >&2
+    exit 1
+fi
+
+if [[ $EUID -ne 0 ]]; then
+    echo "Run as root (sudo)." >&2
+    exit 1
+fi
+
+echo "==> Installing ltp305 Python package from vendored source"
+pip3 install --break-system-packages "$REPO_DIR/vendor/ltp305-python/library"
+
+echo "==> Deploying script tree to $TARGET_HOME/Pimoroni/ltp305"
+mkdir -p "$TARGET_HOME/Pimoroni"
+cp -r "$REPO_DIR/deployed/home/dissimulo/Pimoroni/ltp305" "$TARGET_HOME/Pimoroni/"
+chown -R "$TARGET_USER:$TARGET_USER" "$TARGET_HOME/Pimoroni"
+
+echo "==> Installing systemd units"
+install -m 0644 "$REPO_DIR/systemd/matrix0x61.service" /etc/systemd/system/matrix0x61.service
+install -m 0644 "$REPO_DIR/systemd/matrix0x63.service" /etc/systemd/system/matrix0x63.service
+
+echo "==> Reloading systemd and enabling units"
+systemctl daemon-reload
+systemctl enable --now matrix0x61.service matrix0x63.service
+
+echo
+echo "Done. Status:"
+systemctl --no-pager status matrix0x61.service matrix0x63.service || true