Add authenticated global economic calendar with Jin10 fallback

Collect macroeconomic releases, events and holidays through the official browser SDK with resumable history from 2025. Preserve evidence, revisions and observation times, and merge verified series with official fields taking priority.

Add category filters, field provenance, coverage and connection status. Verify calendar persistence and deployment recovery in isolated acceptance checks.

backend/src/alphapulse/api/jin10.py

@@ -1,5 +1,6 @@
 """Administrator-only Jin10 connection; credentials never leave the backend."""
 from datetime import UTC, datetime, timedelta
+import json
 import secrets
 from typing import Annotated
 
@@ -12,6 +13,7 @@ from alphapulse.calendar import jin10_auth
 from alphapulse.core.auth import AuthSession, check_session, require_admin
 from alphapulse.core.crypto import decrypt, encrypt
 from alphapulse.core.db import get_session
+from alphapulse.core.redis import KEY_PREFIX, redis
 from alphapulse.models.jin10 import Jin10Connection
 
 router = APIRouter(prefix="/api/settings/jin10", tags=["settings"], dependencies=[Depends(require_admin)])
@@ -33,14 +35,21 @@ def clear_task(row: Jin10Connection) -> None:
     row.task_id = row.owner = row.qr_encrypted = row.expires_at = row.next_poll_at = None
 
 
-def public_status(row: Jin10Connection) -> dict:
+def public_status(row: Jin10Connection, sync: dict | None = None) -> dict:
+    current = bool(row.token_encrypted and row.connected_at and sync and sync.get("connected_at") == row.connected_at.isoformat()
+                   and datetime.now(UTC) - datetime.fromisoformat(sync["at"]) < timedelta(seconds=30))
     return {"connected": row.token_encrypted is not None, "connected_at": row.connected_at,
-            "error": row.error, "sync_state": "awaiting_validation" if row.token_encrypted else "disconnected"}
+            "error": row.error or (sync.get("error") if current else None),
+            "sync_state": sync["state"] if current else "awaiting_validation" if row.token_encrypted else "disconnected",
+            "last_success_at": sync.get("last_success_at") if current else None,
+            "history_next": sync.get("history_next") if current else None}
 
 
 @router.get("")
 async def status(session: Session) -> ApiResponse[dict]:
-    return success(public_status(await connection(session)))
+    row = await connection(session)
+    raw = await redis.get(f"{KEY_PREFIX}calendar:jin10")
+    return success(public_status(row, json.loads(raw) if raw else None))
 
 
 @router.post("/qr", status_code=201)