refactor: start _get_addon_logs_via_supervisor docstring with action verb

Per Gemini review on PR homeassistant-ai#1126: aligns the internal helper's docstring
with the action-verb shape of nearby Fetch*/Get* methods on
HomeAssistantClient. The .gemini/styleguide.md MCP-Tool-Docstrings
section technically scopes to public @tool functions, so this is a
consistency-nit rather than a styleguide-mandated fix — but matches the
local pattern.

Author: Patch76

src/ha_mcp/client/rest_client.py

@@ -470,7 +470,7 @@ async def get_addon_logs(self, slug: str) -> str:
         return response.text
 
     async def _get_addon_logs_via_supervisor(self, slug: str) -> str:
-        """Direct Supervisor REST API fetch for add-on installs.
+        """Fetch add-on logs directly from the Supervisor REST API.
 
         Mirrors the access pattern used by ``tools_bug_report._fetch_addon_logs``:
         a fresh ``httpx.AsyncClient`` against ``http://supervisor`` authed with