feat: agent updates from SAC, poll config, SSH/WinRM fallback (0.12.0)

Add agent update settings, pending self-update via poll, desired config per host, and automatic or manual SSH/WinRM fallback when agents do not report agent.update events.

backend/app/schemas/list_models.py

@@ -18,6 +18,8 @@ class HostSummary(BaseModel):
     last_daily_report_at: datetime | None = None
     last_inventory_at: datetime | None = None
     agent_status: str = "unknown"
+    version_status: str = "unknown"
+    pending_agent_update: bool = False
 
     model_config = {"from_attributes": True}
 
@@ -32,6 +34,13 @@ class HostDetail(HostSummary):
     created_at: datetime | None = None
     ssh_admin_ok: bool | None = None
     ssh_admin_checked_at: datetime | None = None
+    pending_update_requested_at: datetime | None = None
+    pending_update_target_version: str | None = None
+    agent_config_revision: int = 0
+    agent_config: dict | None = None
+    agent_update_state: str | None = None
+    agent_update_last_at: datetime | None = None
+    agent_update_last_error: str | None = None
 
 
 class HostListResponse(BaseModel):