fix: advertise retry delay on context timeout (#40)

src/main.py

@@ -1,4 +1,5 @@
 import asyncio
+import math
 
 from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
@@ -75,7 +76,9 @@ async def context() -> JSONResponse:
                 {"panel": "gitea", "action": "set GITEA_URL + GITEA_TOKEN", "target": "/root/stackchain-dashboard/.env or systemd env", "priority": "high"},
             ],
             "error": error_message,
-        })
+        }, headers={
+            "Retry-After": str(max(1, math.ceil(CONTEXT_TIMEOUT_SECONDS)))
+        } if isinstance(e, TimeoutError) else None)
     user_model = User(id=user_data["id"], login=user_data["login"], full_name=user_data.get("full_name", ""), email=user_data.get("email", ""))
     repo_models = [
         Repo(id=r["id"], name=r["name"], full_name=r["full_name"], description=r.get("description", ""), url=r["html_url"], updated_at=r.get("updated_at", ""))

src/release_engine.py

@@ -147,6 +147,8 @@ class GiteaClient:
                 return json.loads(raw) if raw else None
         except error.HTTPError as exc:
             detail = exc.read().decode(errors="replace")
+            if exc.code == 401:
+                detail += " (authentication rejected; refresh the cron GITEA_TOKEN)"
             raise RuntimeError(f"Gitea {method} {path} failed: HTTP {exc.code}: {detail}") from exc
 
     @staticmethod

tests/test_context_timeout.py

@@ -27,6 +27,7 @@ async def test_context_returns_fallback_when_gitea_exceeds_deadline(monkeypatch)
     response = await main.context()
 
     assert response.status_code == 200
+    assert response.headers["retry-after"] == "1"
     assert b'"repos":[]' in response.body
     assert b'"error":"Gitea context request timed out after 0.01s"' in response.body
     assert cancelled.is_set()

tests/test_release_engine.py

@@ -1,4 +1,6 @@
 import json
+import threading
+from http.server import BaseHTTPRequestHandler, HTTPServer
 from pathlib import Path
 
 import pytest
@@ -6,6 +8,7 @@ import pytest
 from src.release_engine import (
     CommandResult,
     EngineConfig,
+    GiteaClient,
     Issue,
     ReleaseEngine,
     RunState,
@@ -15,6 +18,28 @@ from src.release_engine import (
 )
 
 
+def test_stale_token_error_explains_how_to_restore_cron_authentication():
+    class UnauthorizedHandler(BaseHTTPRequestHandler):
+        def do_GET(self):
+            self.send_response(401)
+            self.end_headers()
+            self.wfile.write(b'{"message":"user does not exist [uid: 0, name: ]"}')
+
+        def log_message(self, format, *args):
+            pass
+
+    server = HTTPServer(("127.0.0.1", 0), UnauthorizedHandler)
+    thread = threading.Thread(target=server.handle_request)
+    thread.start()
+    try:
+        client = GiteaClient(f"http://127.0.0.1:{server.server_port}", "stale-token")
+        with pytest.raises(RuntimeError, match="refresh the cron GITEA_TOKEN"):
+            client.list_open_issues("stackchain/stackchain-dashboard")
+    finally:
+        thread.join(timeout=2)
+        server.server_close()
+
+
 class FakeClient:
     def __init__(self, issues, verified_assignee="timmy", existing_pr=None):
         self.issues = issues