report per-ticker R:R scanner progress (sidebar stuck at 0%)

scan_rr set the total then called scan_all_tickers as one opaque await, so the
runtime snapshot's processed count stayed 0 until the whole scan finished and
jumped straight to 100%. scan_all_tickers now takes an optional progress_callback
invoked per ticker; the scheduler wires it to _runtime_progress so the sidebar's
live indicator advances as tickers are scanned.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

app/services/rr_scanner_service.py

@@ -10,6 +10,7 @@ from __future__ import annotations
 
 import json
 import logging
+from collections.abc import Callable
 from datetime import datetime, timezone
 
 from sqlalchemy import and_, func, select
@@ -237,13 +238,21 @@ async def scan_all_tickers(
     db: AsyncSession,
     rr_threshold: float = 1.5,
     atr_multiplier: float = 1.5,
+    progress_callback: Callable[[int, int, str], None] | None = None,
 ) -> list[TradeSetup]:
-    """Scan all tracked tickers for trade setups."""
+    """Scan all tracked tickers for trade setups.
+
+    ``progress_callback(processed, total, current_symbol)`` is invoked as each
+    ticker is scanned so callers (e.g. the scheduler) can surface live progress.
+    """
     result = await db.execute(select(Ticker).order_by(Ticker.symbol))
     tickers = list(result.scalars().all())
+    total = len(tickers)
 
     all_setups: list[TradeSetup] = []
-    for ticker in tickers:
+    for index, ticker in enumerate(tickers):
+        if progress_callback is not None:
+            progress_callback(index, total, ticker.symbol)
         try:
             # Refresh scores first so the scheduled scan works off current data.
             # Nothing else marks scores stale, so without this they'd never
@@ -264,6 +273,9 @@ async def scan_all_tickers(
         except Exception:
             logger.exception("Error scanning ticker %s", ticker.symbol)
 
+    if progress_callback is not None and total:
+        progress_callback(total, total, "")
+
     return all_setups