Scan survives score-refresh failures; fix expired-ORM crash after rollback

A scoring error no longer skips setup detection for the ticker: the
rollback already restores a clean transaction, and qualification
re-gates on live scores at alert time, so a stale score is recoverable
but a skipped scan is not.

Iterating symbol strings instead of Ticker instances fixes a latent
crash the new regression test caught: rollback() expires ORM objects
regardless of expire_on_commit, so touching ticker.symbol in the except
handler triggered sync lazy-loading, which raises on an AsyncSession
and killed the whole scan on the first per-ticker error.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/unit/test_rr_scanner_scan_all.py

@@ -0,0 +1,61 @@
+"""Tests for scan_all_tickers orchestration: error isolation between phases."""
+
+from __future__ import annotations
+
+import pytest
+
+from app.models.ticker import Ticker
+from app.services import rr_scanner_service, scoring_service
+from tests.conftest import _test_session_factory  # type: ignore
+
+
+@pytest.fixture
+async def session():
+    async with _test_session_factory() as s:
+        yield s
+
+
+async def test_scan_proceeds_when_score_refresh_fails(session, monkeypatch):
+    """A scoring failure must not skip setup detection for the ticker.
+
+    Qualification re-gates on live scores at alert time, so a stale score is
+    recoverable — a skipped scan is not.
+    """
+    session.add(Ticker(symbol="AAA"))
+    await session.commit()
+
+    async def _boom(db, symbol):
+        raise RuntimeError("scoring unavailable")
+
+    scanned: list[str] = []
+
+    async def _fake_scan_ticker(db, symbol, *args, **kwargs):
+        scanned.append(symbol)
+        return []
+
+    monkeypatch.setattr(scoring_service, "compute_all_dimensions", _boom)
+    monkeypatch.setattr(rr_scanner_service, "scan_ticker", _fake_scan_ticker)
+
+    setups = await rr_scanner_service.scan_all_tickers(session)
+
+    assert scanned == ["AAA"]
+    assert setups == []
+
+
+async def test_scan_error_does_not_stop_later_tickers(session, monkeypatch):
+    session.add_all([Ticker(symbol="AAA"), Ticker(symbol="BBB")])
+    await session.commit()
+
+    scanned: list[str] = []
+
+    async def _fake_scan_ticker(db, symbol, *args, **kwargs):
+        scanned.append(symbol)
+        if symbol == "AAA":
+            raise RuntimeError("scan blew up")
+        return []
+
+    monkeypatch.setattr(rr_scanner_service, "scan_ticker", _fake_scan_ticker)
+
+    await rr_scanner_service.scan_all_tickers(session)
+
+    assert scanned == ["AAA", "BBB"]