feat(devices): BLE LED controller support (SP110E/Triones/Zengge/Govee)

End-to-end BLE streaming: provider + client + per-protocol wire encoders
with whole-strip averaging, desktop (bleak) and Android (Kotlin BleBridge
via Chaquopy) transports, discovery with protocol-family detection that
auto-fills the UI, throttled not-connected warning + 10 s reconnect
cooldown so a dropped link no longer stalls the pipeline at ~30 s/frame,
and an explicit asyncio.wait_for wrapper around bleak connect() since
the WinRT backend doesn't always honor the timeout kwarg.

Also rewrites server/restart.ps1 to be parameterized (-Port / -Module /
-PythonVersion / timeouts / -Quiet), pick the right interpreter via the
py launcher, pre-flight the target module, poll port readiness on both
shutdown and startup, redirect child stdout/stderr so Start-Process
doesn't hang on inherited Git-Bash handles, and return proper exit codes.

Rolls in concurrent work: Android BLE permissions + launcher icons + ru/zh
resources, Chaquopy-safe value_stream psutil fallback, setup-required
modal, asset-store test coverage, and misc system/config touch-ups.

server/tests/test_config.py

@@ -1,5 +1,7 @@
 """Tests for configuration management."""
 
+from pathlib import Path
+
 import pytest
 import yaml
 
@@ -18,10 +20,23 @@ class TestDefaultConfig:
         assert config.server.port == 8080
         assert config.server.log_level == "INFO"
 
-    def test_default_storage_paths(self):
+    def test_default_storage_paths(self, monkeypatch):
+        monkeypatch.delenv("LEDGRAB_DATA_DIR", raising=False)
         config = Config()
         assert config.storage.database_file == "data/ledgrab.db"
 
+    def test_data_dir_env_override(self, monkeypatch, tmp_path):
+        monkeypatch.setenv("LEDGRAB_DATA_DIR", str(tmp_path / "custom"))
+        # default_data_dir reads the env var, but the module-level default
+        # was evaluated at import time — so re-import paths() value via the
+        # helper to confirm the contract.
+        from importlib import reload
+
+        from ledgrab import paths as paths_mod
+
+        reload(paths_mod)
+        assert paths_mod.default_data_dir() == Path(str(tmp_path / "custom"))
+
     def test_default_mqtt_disabled(self):
         config = Config()
         assert config.mqtt.enabled is False
@@ -71,9 +86,15 @@ class TestServerConfig:
 class TestDemoMode:
     def test_demo_rewrites_storage_paths(self):
         config = Config(demo=True)
-        assert config.storage.database_file.startswith("data/demo/")
+        db_path = Path(config.storage.database_file)
+        assert db_path.parent.name == "demo"
+        assert db_path.name == "ledgrab.db"
+        assets_path = Path(config.assets.assets_dir)
+        assert assets_path.parent.name == "demo"
+        assert assets_path.name == "assets"
 
-    def test_non_demo_keeps_original_paths(self):
+    def test_non_demo_keeps_original_paths(self, monkeypatch):
+        monkeypatch.delenv("LEDGRAB_DATA_DIR", raising=False)
         config = Config(demo=False)
         assert config.storage.database_file == "data/ledgrab.db"