fix: 3 bugs — synthesis crash, stale running cycle, invalid tickers

- knowledge.py: trade_line crash when pnl_pct is None in dict
  (t.get('pnl_pct',0) returns None if key exists with None value — use 'or 0')
- database.py: cleanup_stale_running_cycles() marks any 'running' cycle
  as 'error' on startup (uvicorn reload mid-cycle left status stuck)
- main.py: call cleanup_stale_running_cycles() at startup with warning log
- database.py: _normalize_ticker() converts GPT-4o exchange:symbol format
  (NSE:RELIANCE → RELIANCE.NS, BSE:X → X.BO, etc.) so yfinance stops
  spamming 404 errors for every MTM request

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

backend/main.py

@@ -1,7 +1,7 @@
 from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
 from routers import market_data, geopolitical, options, backtest, ai, portfolio, config, patterns, journal, cycle as cycle_router, profiles as profiles_router, reasoning as reasoning_router, knowledge as knowledge_router
-from services.database import init_db, get_config
+from services.database import init_db, get_config, cleanup_stale_running_cycles
 import os
 import uvicorn
 
@@ -23,6 +23,13 @@ app.add_middleware(
 @app.on_event("startup")
 def startup():
     init_db()
+    # Clean up cycles that were left in 'running' state by a previous crashed process
+    stale = cleanup_stale_running_cycles()
+    if stale:
+        import logging
+        logging.getLogger(__name__).warning(
+            f"[Startup] Cleaned up {stale} stale 'running' cycle(s) — server likely reloaded mid-cycle"
+        )
     key = get_config("openai_api_key") or ""
     if key:
         os.environ["OPENAI_API_KEY"] = key