feat: EUR/USD simulator — live baseline from market data

Backend (routers/simulator.py):
- GET /api/simulator/baseline aggregates current market values:
  1. macro_gauge_snapshots → VIX, Brent oil
  2. FRED economic_events  → FEDFUNDS, ECBDFR, DFII10 (real yield)
  3. yfinance live         → EURUSD=X, ^IRX+^FVX interpolated US 2Y,
                             DE2YT=RR EU 2Y (or ECB rate +15bps fallback),
                             ^VIX, BZ=F
- Returns sources dict so frontend can show data provenance

Frontend (EuroSimulator.tsx):
- Fetch /api/simulator/baseline on mount; use as base anchors
- compute(p, base) now takes dynamic base instead of hardcoded constants
- Reset button returns to today's live baseline, not hardcoded fallback
- Live/Fallback status badge with fetch date
- Sources panel showing data origin per field
- Chart reference line updates to show live base values

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

backend/main.py

@@ -14,6 +14,7 @@ from routers import var as var_router
 from routers import reports as reports_router
 from routers import institutional as institutional_router
 from routers import eco as eco_router
+from routers import simulator as simulator_router
 from services.database import init_db, get_config, cleanup_stale_running_cycles
 import os
 import logging
@@ -196,6 +197,7 @@ app.include_router(cycle_actions_router.router)
 app.include_router(market_events_router.router)
 app.include_router(ai_desks_router.router)
 app.include_router(eco_router.router)
+app.include_router(simulator_router.router)
 
 
 @app.get("/")