feat: system logs page + dynamic IV watchlist with auto-add from cycle

Backend:
- DB: add system_logs table (level/source/cycle_id/ticker/message) and
  iv_watchlist table (ticker/added_by/is_active); seed builtin 18 tickers
- DBLogHandler attached at startup — all WARNING+ logs auto-persist to DB
- log_system_event() helper for structured manual events
- New router /api/logs: GET with filters (level, source, cycle_id, ticker,
  date range), GET /sources, GET /cycles for dropdowns, DELETE /clear
- iv_watchlist now read from DB instead of hardcoded constant; options_vol
  watchlist/refresh/bootstrap endpoints all use get_watchlist_tickers()
- New endpoints: POST/DELETE /options-vol/watchlist-tickers/{ticker} to
  add/remove tickers; adding triggers background 1-year bootstrap
- auto_cycle: after log_trade_entries(), auto-detect new underlying proxies
  not yet in watchlist, add them and bootstrap their IV history

Frontend:
- New page SystemLogs (/logs): log table with level/source/cycle/ticker/date
  filters, color-coded rows, expandable JSON details, auto-refresh 30s
- Options Lab: WatchlistManager section — add ticker input, chip list with
  builtin/auto/manual color coding, remove button for non-builtins
- Sidebar: Logs Système nav link (ScrollText icon)
- useApi: useSystemLogs, useLogSources, useLogCycles, useClearLogs,
  useWatchlistTickers, useAddWatchlistTicker, useRemoveWatchlistTicker

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

backend/main.py

@@ -1,10 +1,30 @@
 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, options_vol as options_vol_router, analytics as analytics_router, risk as risk_router
+from routers import logs as logs_router
 from services.database import init_db, get_config, cleanup_stale_running_cycles
 import os
+import logging
 import uvicorn
 
+
+class _DBLogHandler(logging.Handler):
+    """Persist WARNING+ log records to system_logs table."""
+    def emit(self, record: logging.LogRecord):
+        if record.levelno < logging.WARNING:
+            return
+        try:
+            from services.database import log_system_event
+            log_system_event(
+                level=record.levelname,
+                source=record.name,
+                message=self.format(record),
+                cycle_id=getattr(record, "cycle_id", None),
+                ticker=getattr(record, "ticker", None),
+            )
+        except Exception:
+            pass  # Never raise from inside a log handler
+
 app = FastAPI(
     title="GeoOptions Intelligence",
     description="Geopolitical Options Trading Cockpit API",
@@ -22,7 +42,11 @@ app.add_middleware(
 
 @app.on_event("startup")
 def startup():
-    import logging
+    # Attach DB log handler to root logger (captures WARNING+ from all modules)
+    _db_handler = _DBLogHandler()
+    _db_handler.setFormatter(logging.Formatter("%(message)s"))
+    logging.getLogger().addHandler(_db_handler)
+
     _log = logging.getLogger(__name__)
 
     init_db()
@@ -74,6 +98,7 @@ app.include_router(knowledge_router.router)
 app.include_router(options_vol_router.router)
 app.include_router(analytics_router.router)
 app.include_router(risk_router.router)
+app.include_router(logs_router.router)
 
 
 @app.get("/")