[hAIk]: refactor AgentCard and BrowserCard into subdirectory modules, plumb dashboard_id from launch through Agent/AgentSnapshot, add on_done auto-persist callback, fix get_all_sessions to use GET query params, atomic PydanticStore writes, graceful backend shutdown in local.sh, and add mode config JSONs

backend/core/shared_structs/agent/AgentSnapshot.py

@@ -9,6 +9,7 @@ class AgentSnapshot(BaseModel):
     model: str
     mode: str
     status: str
+    dashboard_id: Optional[str] = None
     branch_id: str = "main"
     parent_id: Optional[str] = None
     messages: MessageLog = Field(default_factory=MessageLog)