feat(host-agent): report assignment outcomes

apps/device-host-agent/tests/test_client.py

@@ -1,6 +1,7 @@
 from __future__ import annotations
 
 import asyncio
+import json
 from datetime import UTC, datetime
 
 import httpx
@@ -131,3 +132,37 @@ def test_stale_lease_response_raises_typed_error_without_retry() -> None:
 
     asyncio.run(scenario())
     assert attempts == 1
+
+
+def test_result_report_retries_identical_payload_after_response_loss() -> None:
+    payloads: list[dict[str, object]] = []
+
+    def handler(request: httpx.Request) -> httpx.Response:
+        payloads.append(json.loads(request.content))
+        if len(payloads) == 1:
+            raise httpx.ReadError("response lost", request=request)
+        return httpx.Response(200, json={"status": "already_recorded"})
+
+    async def scenario() -> None:
+        async with httpx.AsyncClient(
+            transport=httpx.MockTransport(handler),
+            base_url="https://control.example",
+        ) as http_client:
+            client = HostAgentClient(
+                _config(),
+                http_client=http_client,
+                sleep=lambda delay: asyncio.sleep(0),
+            )
+            response = await client.report_result(
+                _assignment(),
+                status="failed",
+                failure_reason="planner unavailable",
+                result={"runtime_status": "failed"},
+            )
+
+        assert response.status == "already_recorded"
+
+    asyncio.run(scenario())
+    assert len(payloads) == 2
+    assert payloads[0] == payloads[1]
+    assert payloads[0]["failure_reason"] == "planner unavailable"