fix(run): drop first_accepted gate from catchup synth-arm

Catchup branch gated on first_accepted, but an earlier accepted gray tick
consumes the flag before a dark_* arrives, so the real prime-phase color
falls through to noise classification and no alert fires. Gate on
IDLE + dark_* alone — self-sufficient and correct.

Regression: 2 unit tests for _handle_tick + 1 integration test feeding
run_live a scripted gray→gray→dark_red→dark_red→light_red sequence.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

tests/test_main.py

@@ -135,3 +135,123 @@ def test_run_live_dry(monkeypatch):
 
     assert len(calls) == 1
     assert calls[0]["duration_s"] == pytest.approx(0.0)
+
+
+# ---------------------------------------------------------------------------
+# Regression integration test — user bug 2026-04-16.
+# Session starts with an accepted gray tick followed by dark_red. Catchup
+# synth-arm must fire on dark_red (the previous gray consumed first_accepted),
+# then light_red triggers SELL. Proves run_live wiring dispatches alerts for
+# the user's exact scenario.
+# ---------------------------------------------------------------------------
+
+def test_run_live_catchup_sell_from_gray_then_dark_red(monkeypatch, tmp_path):
+    import numpy as np
+    import atm.main as _main
+    from atm.detector import DetectionResult
+
+    captured = []
+
+    class FakeFanout:
+        def __init__(self, *a, **kw):
+            pass
+        def send(self, alert):
+            captured.append(alert)
+        def stop(self):
+            pass
+
+    class FakeCanaryResult:
+        distance = 0
+        drifted = False
+        paused = False
+
+    class FakeCanary:
+        def __init__(self, *a, **kw):
+            self.is_paused = False
+        def check(self, frame):
+            return FakeCanaryResult()
+        def resume(self):
+            pass
+
+    class _StopLoop(Exception):
+        pass
+
+    class ScriptedDetector:
+        _script = [
+            ("gray", True),
+            ("gray", True),
+            ("dark_red", True),
+            ("dark_red", True),
+            ("light_red", True),
+        ]
+        def __init__(self, *a, **kw):
+            self._i = 0
+        def step(self, ts):
+            if self._i >= len(self._script):
+                raise _StopLoop
+            color, accepted = self._script[self._i]
+            self._i += 1
+            return DetectionResult(
+                ts=ts,
+                window_found=True,
+                dot_found=True,
+                rgb=(1, 1, 1),
+                match=None,
+                accepted=accepted,
+                color=color,
+            )
+
+    def fake_build_capture(cfg, capture_stub=False):
+        return lambda: np.zeros((50, 50, 3), dtype=np.uint8)
+
+    cfg = MagicMock()
+    cfg.lockout_s = 60
+    cfg.heartbeat_min = 999
+    cfg.loop_interval_s = 0
+    cfg.config_version = "test"
+    cfg.dead_letter_path = str(tmp_path / "dl.jsonl")
+    cfg.canary.drift_threshold = 10
+    cfg.dot_roi.x = 0
+    cfg.dot_roi.y = 0
+    cfg.dot_roi.w = 10
+    cfg.dot_roi.h = 10
+    cfg.chart_window_region = None
+
+    monkeypatch.chdir(tmp_path)
+    class _Stub:
+        def __init__(self, *a, **kw):
+            pass
+        def log(self, *a, **kw):
+            pass
+        def close(self, *a, **kw):
+            pass
+        def step(self, *a, **kw):
+            return types.SimpleNamespace(status="pending", levels=None)
+
+    monkeypatch.setattr("atm.detector.Detector", ScriptedDetector)
+    monkeypatch.setattr("atm.canary.Canary", FakeCanary)
+    monkeypatch.setattr("atm.notifier.fanout.FanoutNotifier", FakeFanout)
+    monkeypatch.setattr("atm.notifier.discord.DiscordNotifier", _Stub)
+    monkeypatch.setattr("atm.notifier.telegram.TelegramNotifier", _Stub)
+    monkeypatch.setattr("atm.audit.AuditLog", _Stub)
+    monkeypatch.setattr("atm.levels.LevelsExtractor", _Stub)
+    monkeypatch.setattr("atm.main._build_capture", fake_build_capture)
+    monkeypatch.setattr("atm.main.time.sleep", lambda s: None)
+
+    with pytest.raises(_StopLoop):
+        _main.run_live(cfg, duration_s=None)
+
+    arm = [a for a in captured if a.kind == "arm"]
+    prime = [a for a in captured if a.kind == "prime"]
+    trigger = [a for a in captured if a.kind == "trigger"]
+
+    assert len(arm) == 1, f"expected 1 arm alert, got {len(arm)} ({[a.title for a in captured]})"
+    assert arm[0].direction == "SELL"
+    assert "catchup" in (arm[0].title + arm[0].body).lower()
+
+    assert len(prime) == 1
+    assert prime[0].direction == "SELL"
+    assert "catchup" in (prime[0].title + prime[0].body).lower()
+
+    assert len(trigger) == 1
+    assert trigger[0].direction == "SELL"