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/api/v1/agent.py

@@ -7,11 +7,10 @@ from sqlalchemy.orm import Session
 from app.auth.api_key import get_api_key_auth
 from app.database import get_db
 from app.services.agent_commands import (
-    command_to_dict,
     complete_command,
-    get_command_for_host_poll,
     resolve_host_by_agent_instance_id,
 )
+from app.services.agent_poll import build_agent_poll_payload
 
 router = APIRouter(prefix="/agent", tags=["agent"])
 
@@ -23,7 +22,10 @@ class AgentCommandResultBody(BaseModel):
 
 
 class AgentCommandsPollResponse(BaseModel):
-    commands: list[dict[str, Any]]
+    config_revision: int = 0
+    config: dict[str, Any] = Field(default_factory=dict)
+    update: dict[str, Any] = Field(default_factory=dict)
+    commands: list[dict[str, Any]] = Field(default_factory=list)
 
 
 @router.get("/commands", response_model=AgentCommandsPollResponse)
@@ -35,10 +37,8 @@ def poll_agent_commands(
     host = resolve_host_by_agent_instance_id(db, agent_instance_id)
     if host is None:
         raise HTTPException(status_code=404, detail="Unknown agent_instance_id")
-    pending = get_command_for_host_poll(db, host)
-    return AgentCommandsPollResponse(
-        commands=[command_to_dict(c, include_run_as=True) for c in pending]
-    )
+    payload = build_agent_poll_payload(db, host)
+    return AgentCommandsPollResponse(**payload)
 
 
 @router.post("/commands/{command_uuid}/result")