ha: add li3_battery HA integration, replacing van-li3-battery

The li3 BMS has a persistently marginal BLE link from any single fixed
vantage point on this Pi (onboard adapter, a USB dongle that turned out to
be BR/EDR-only, and the Athom ESPHome BT proxy even after moving it closer).
Move capture into HA proper so bluetooth.async_ble_device_from_address can
pick whichever known source currently has the device, instead of hardcoding
one. Protocol parsing ported verbatim from li3/van-li3-battery.

van-li3-battery is disabled on the Pi; its MQTT discovery entities were
cleared.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

ha/custom_components/li3_battery/manifest.json

@@ -0,0 +1,17 @@
+{
+  "domain": "li3_battery",
+  "name": "Lithionics Li3 BMS",
+  "codeowners": ["@aew"],
+  "config_flow": true,
+  "dependencies": ["bluetooth"],
+  "documentation": "https://github.com/wrede/vanlink",
+  "iot_class": "local_push",
+  "requirements": ["bleak-retry-connector>=3.0.0"],
+  "version": "0.1.0",
+  "bluetooth": [
+    {
+      "local_name": "Li3-*",
+      "connectable": true
+    }
+  ]
+}