feat: FF HTML scraper for upcoming weeks with forecasts

- scrape_upcoming(weeks_ahead=5) in ff_calendar.py:
  fetches forexfactory.com/calendar?week=... HTML for N weeks ahead,
  parses calendar__table (date/time/currency/impact/event/forecast/previous),
  converts ET times to UTC, upserts into ff_calendar
- Daily scheduler in main.py: runs scrape_upcoming at startup (after 30s delay)
  then every 24h — no manual action needed
- New endpoints: POST /api/eco/ff-scrape?weeks=5, GET /api/eco/ff-scrape/status
- CalendarPage: "Scrape Upcoming (5w)" button (indigo) with polling + result

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

backend/main.py

@@ -95,6 +95,22 @@ def startup():
     from services.institutional_scheduler import start_institutional_scheduler
     start_institutional_scheduler()
 
+    # Daily FF scraper — runs once at startup, then every 24h
+    import threading, time as _time
+    def _ff_scrape_loop():
+        _time.sleep(30)  # let server fully boot first
+        while True:
+            try:
+                print("[Startup] FF scrape upcoming weeks …", flush=True)
+                from services.ff_calendar import scrape_upcoming
+                result = scrape_upcoming(weeks_ahead=5)
+                print(f"[FF scrape] done: {result.get('total_upserted', 0)} upserted", flush=True)
+            except Exception as e:
+                print(f"[FF scrape] loop error: {e}", flush=True)
+            _time.sleep(86400)  # 24h
+
+    threading.Thread(target=_ff_scrape_loop, daemon=True).start()
+
     # Auto-import Forex Factory CSV if file is present (force, then delete CSV)
     import threading
     def _auto_import_ff():