Add run_context to agent tool calls for FE run logging

- AgentTriggerRequest accepts optional agent_id (FE's stable electron-store UUID)
- _make_agent_executor injects run_context into every tool_call frame
  so Electron can attribute actions to the correct agent run
- run_local_agent accepts run_context and sends a run_complete WS frame
  when the run finishes so the FE can close the run record
- trigger_agent_run builds run_context with run_id=run_log.id and the
  stable agent_id, passes it through to run_local_agent

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/schemas.py

@@ -295,6 +295,7 @@ class AgentCreationCheckResponse(BaseModel):
 class AgentTriggerRequest(BaseModel):
     directory: str = Field(min_length=1)
     device_id: str = Field(default="")
+    agent_id: str | None = None  # FE stable agent ID (electron-store UUID)
     what_to_extract: list[str] = Field(min_length=1)
     actions_by_type: dict[str, list[str]] | None = None
     batch_interval: str = Field(min_length=1)