Fix broker session showing connected after Zerodha token expiry

- Set connected=FALSE (was TRUE) when expiring broker session so the
  dashboard correctly reflects disconnected state
- Notify user by email when their Zerodha session expires so they know
  to reconnect before the next SIP execution

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/app/broker_store.py

@@ -162,7 +162,7 @@ def expire_user_broker_session(user_id: str):
         cur.execute(
             """
             UPDATE user_broker
-            SET connected = TRUE,
+            SET connected = FALSE,
                 access_token = NULL,
                 auth_state = 'EXPIRED'
             WHERE user_id = %s

backend/app/routers/zerodha.py

@@ -5,6 +5,7 @@ from fastapi.responses import HTMLResponse
 
 from app.broker_store import expire_user_broker_session
 from app.services.auth_service import get_user_for_session
+from app.services.email_service import send_email_async
 from app.services.live_equity_service import (
     capture_live_equity_snapshot,
     get_live_equity_curve,
@@ -48,14 +49,24 @@ def _capture_request_token(request: Request, request_token: str):
     store_request_token(user["id"], token)
 
 
-def _clear_broker_session(user_id: str):
+def _clear_broker_session(user_id: str, email: str | None = None):
     expire_user_broker_session(user_id)
     clear_session(user_id)
+    if email:
+        try:
+            body = (
+                "Your Zerodha session has expired and your broker connection has been disconnected.\n\n"
+                "Please log in to QuantFortune and reconnect your Zerodha account to resume your strategy.\n\n"
+                "If your strategy was running, it has been paused until you reconnect."
+            )
+            send_email_async(email, "Action required: Zerodha session expired", body)
+        except Exception:
+            pass
 
 
-def _raise_kite_error(user_id: str, exc: KiteApiError):
+def _raise_kite_error(user_id: str, exc: KiteApiError, email: str | None = None):
     if isinstance(exc, KiteTokenError):
-        _clear_broker_session(user_id)
+        _clear_broker_session(user_id, email=email)
         raise HTTPException(
             status_code=401, detail="Zerodha session expired. Please reconnect."
         ) from exc
@@ -139,7 +150,7 @@ async def holdings(request: Request):
     try:
         data = fetch_holdings(session["api_key"], session["access_token"])
     except KiteApiError as exc:
-        _raise_kite_error(user["id"], exc)
+        _raise_kite_error(user["id"], exc, email=user["username"])
     return {"holdings": [normalize_holding(item) for item in data]}
 
 
@@ -152,7 +163,7 @@ async def funds(request: Request):
     try:
         data = fetch_funds(session["api_key"], session["access_token"])
     except KiteApiError as exc:
-        _raise_kite_error(user["id"], exc)
+        _raise_kite_error(user["id"], exc, email=user["username"])
     equity = data.get("equity", {}) if isinstance(data, dict) else {}
     return {"funds": {**equity, "raw": data}}
 
@@ -168,7 +179,7 @@ async def equity_curve(request: Request, from_: str = Query("", alias="from")):
         holdings = fetch_holdings(session["api_key"], session["access_token"])
         funds_data = fetch_funds(session["api_key"], session["access_token"])
     except KiteApiError as exc:
-        _raise_kite_error(user["id"], exc)
+        _raise_kite_error(user["id"], exc, email=user["username"])
 
     try:
         capture_live_equity_snapshot(
@@ -177,7 +188,7 @@ async def equity_curve(request: Request, from_: str = Query("", alias="from")):
             funds_data=funds_data,
         )
     except KiteApiError as exc:
-        _raise_kite_error(user["id"], exc)
+        _raise_kite_error(user["id"], exc, email=user["username"])
 
     now = datetime.utcnow()
     default_start = (now - timedelta(days=90)).date()

backend/tests/test_api_semantics_and_utc.py

@@ -112,3 +112,39 @@ def test_bootstrap_schema_contains_migrated_core_columns_and_tables():
 
     for snippet in required_snippets:
         assert snippet in schema_sql
+
+
+def test_insert_engine_event_serializes_nested_datetimes():
+    from indian_paper_trading_strategy.engine.db import insert_engine_event
+
+    class FakeCursor:
+        def __init__(self):
+            self.params = None
+
+        def execute(self, _sql, params):
+            self.params = params
+
+    cursor = FakeCursor()
+    event_ts = datetime(2026, 4, 15, 9, 0, tzinfo=timezone.utc)
+    payload_ts = datetime(2026, 4, 15, 9, 1, tzinfo=timezone.utc)
+
+    insert_engine_event(
+        cursor,
+        "ORDER_PLACED",
+        data={
+            "order_id": "order-1",
+            "timestamp": payload_ts,
+            "history": [payload_ts],
+        },
+        meta={"checked_at": payload_ts},
+        ts=event_ts,
+        user_id="user-1",
+        run_id="run-1",
+    )
+
+    data_json = cursor.params[4]
+    meta_json = cursor.params[6]
+
+    assert data_json.adapted["timestamp"] == payload_ts.isoformat()
+    assert data_json.adapted["history"] == [payload_ts.isoformat()]
+    assert meta_json.adapted["checked_at"] == payload_ts.isoformat()

indian_paper_trading_strategy/engine/db.py

@@ -2,8 +2,10 @@ import os
 import threading
 import time
 from contextlib import contextmanager
-from datetime import datetime, timedelta, timezone
+from datetime import date, datetime, timedelta, timezone
 from contextvars import ContextVar
+from decimal import Decimal
+from uuid import UUID
 
 import psycopg2
 from psycopg2 import pool
@@ -146,6 +148,22 @@ def _utc_now():
     return datetime.utcnow().replace(tzinfo=timezone.utc)
 
 
+def _json_safe(value):
+    if isinstance(value, datetime):
+        return value.isoformat()
+    if isinstance(value, date):
+        return value.isoformat()
+    if isinstance(value, Decimal):
+        return float(value)
+    if isinstance(value, UUID):
+        return str(value)
+    if isinstance(value, dict):
+        return {str(key): _json_safe(item) for key, item in value.items()}
+    if isinstance(value, (list, tuple, set)):
+        return [_json_safe(item) for item in value]
+    return value
+
+
 def set_context(user_id: str | None, run_id: str | None):
     token_user = _USER_ID.set(user_id)
     token_run = _RUN_ID.set(run_id)
@@ -328,9 +346,9 @@ def insert_engine_event(
             scope_run,
             when,
             event,
-            Json(data) if data is not None else None,
+            Json(_json_safe(data)) if data is not None else None,
             message,
-            Json(meta) if meta is not None else None,
+            Json(_json_safe(meta)) if meta is not None else None,
         ),
     )