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/breakout-garden/autodetect.py

@@ -0,0 +1,123 @@
+#!/usr/bin/env python
+import smbus
+import sys
+
+I2C_BUS = 1
+DEBUG = False
+
+install_mode = False
+
+if len(sys.argv) > 1:
+    if "--install" in sys.argv:
+        install_mode = True
+
+try:
+    bus = smbus.SMBus(I2C_BUS)
+except IOError:
+    print("Unable to access /dev/i2c-{}, please ensure i2c is enabled!".format(I2C_BUS))
+    sys.exit()
+
+
+def check_chip_id(i2c_addr, chip_ids):
+    if len(chip_ids) == 0:
+        return True
+
+    for register in chip_ids:
+        value, size, negate_match = chip_ids[register]
+        reg, reg_size = register
+        if reg_size == 1:
+            if size == 1:
+                read = bus.read_byte_data(i2c_addr, reg)
+            elif size == 2:
+                read = bus.read_word_data(i2c_addr, reg)
+            else:
+                raise RuntimeError("Unsupported Chip ID size: {} byte(s)".format(size))
+
+            if negate_match and value != read:
+                return True
+            elif value == read:
+                return True
+
+        else:
+            # TODO: Support 16-bit registers
+            raise RuntimeError("Unsupported register size: {} byte(s)".format(size))
+
+    return False
+
+
+def get_device(line):
+    parts=[x.strip() for x in line.split(":")]
+
+    i2c_addr = int(parts[0][0:4], 16)
+
+    chip_ids = {}
+
+    if(len(parts[0]) > 4):
+        register_map = parts[0][5:-1].split(',')
+        for mapping in register_map:
+            if '!=' in mapping:
+                register, value = [(int(x, 16), (len(x) - 2) // 2) for x in mapping.split('!=')]
+                chip_ids[register] = value[0], value[1], True
+            else:
+                register, value = [(int(x, 16), (len(x) - 2) // 2) for x in mapping.split('=')]
+                chip_ids[register] = value[0], value[1], False
+
+    return i2c_addr, parts[1], parts[2], parts[3], chip_ids
+
+devices = [get_device(line) for line in open("breakouts.config").read().strip().split("\n")]
+
+addresses = set([device[0] for device in devices])
+
+
+def identify(find_i2c_addr):
+    try:
+        bus.read_byte_data(find_i2c_addr, 0x00)
+    except IOError as e:
+        pass
+
+    for i2c_addr, library, module, name, chip_ids in devices:
+        if i2c_addr == find_i2c_addr and check_chip_id(i2c_addr, chip_ids):
+            installed = True
+            try:
+                __import__(module)
+            except ImportError:
+                installed = False
+            return installed, library, name
+
+    return None, None, None
+
+
+found_addr = []
+found_devices = {}
+
+for i2c_addr in addresses:
+    try:
+        bus.read_byte_data(i2c_addr, 0x00)
+        if DEBUG: print("Found device on: {:02x}".format(i2c_addr))
+        found_addr.append(i2c_addr)
+        installed, library, name = identify(i2c_addr)
+        if installed is None:
+            continue
+        if name not in found_devices:
+            found_devices[name] = [installed, library, [i2c_addr]]
+        else:
+            found_devices[name][2].append(i2c_addr)
+
+    except IOError as e:
+        if DEBUG: print("IOError reading: {:02x}".format(i2c_addr))
+        continue
+
+for name in found_devices:
+    installed, library, i2c_addresses = found_devices[name]
+    format_string = ""
+    if install_mode:
+        format_string = "{name}|{library}|{installed}"
+    else:
+        format_string = "{i2c_addresses}: {name} ({library} {installed})"
+
+    print(format_string.format(
+        i2c_addresses = ",".join(["0x{:02x}".format(i2c_addr) for i2c_addr in i2c_addresses]),
+            name = name,
+            library = library,
+            installed = "installed" if installed else "required"
+        ))