feat(host-agent): add Console task submission with Host self-submission client

Adds a CSRF-protected task submission form to the local Console Tasks page

apps/device-host-agent/host_agent/client.py

@@ -38,6 +38,21 @@ class StaleLeaseError(HostAgentAPIError):
     pass
 
 
+class HostTaskSubmissionUnknownError(RuntimeError):
+    """Raised when a Host self-submission request's Cloud outcome is uncertain.
+
+    This is distinct from :class:`HostAgentAPIError` because the request may
+    have reached the control plane but the response was lost, the server
+    returned a 5xx, or the success payload was malformed. Retrying would
+    duplicate the create, so the caller must treat the task as unknown and
+    surface that to the operator.
+    """
+
+    def __init__(self, reason: str) -> None:
+        super().__init__(f"host task submission outcome is unknown: {reason}")
+        self.reason = reason
+
+
 class HostAgentEnrollmentClient:
     def __init__(
         self,
@@ -172,16 +187,37 @@ class HostAgentClient:
         goal: str,
         device_id: str | None = None,
     ) -> HostTaskSubmissionResponse:
-        response = await self._request(
-            "POST",
-            f"/internal/v1/hosts/{self.config.host_id}/tasks",
-            json={
-                "host_id": self.config.host_id,
-                "goal": goal,
-                "device_id": device_id,
-            },
-        )
-        return HostTaskSubmissionResponse.model_validate(response.json())
+        try:
+            response = await self._client.request(
+                "POST",
+                f"/internal/v1/hosts/{self.config.host_id}/tasks",
+                json={
+                    "host_id": self.config.host_id,
+                    "goal": goal,
+                    "device_id": device_id,
+                },
+                headers={"Authorization": f"Bearer {self.config.token}"},
+            )
+        except httpx.TransportError as exc:
+            raise HostTaskSubmissionUnknownError(str(exc)) from exc
+        if response.status_code >= 500:
+            raise HostTaskSubmissionUnknownError(
+                f"control plane returned status {response.status_code}"
+            )
+        if not response.is_success:
+            _raise_api_error(response, stale_lease=False)
+        try:
+            payload = response.json()
+        except ValueError as exc:
+            raise HostTaskSubmissionUnknownError(
+                "control plane returned malformed success payload"
+            ) from exc
+        try:
+            return HostTaskSubmissionResponse.model_validate(payload)
+        except Exception as exc:
+            raise HostTaskSubmissionUnknownError(
+                "control plane returned malformed success payload"
+            ) from exc
 
     async def claim(self) -> AssignmentModel | None:
         response = await self._request(