feat(run): per-frame detection log at logs/detections/YYYY-MM-DD.jsonl

Writes one JSONL line per detector.step() with ts, rgb, match_name,
distance, confidence, dot_found, window_found, accepted, color.
Captures UNKNOWN classifications and no-dot frames that today's
audit log skips, so the user can verify post-session what colors
the program actually saw.

Reuses AuditLog for daily rotation + buffering. Separate subdir
keeps audit.jsonl uncluttered.

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

src/atm/main.py

@@ -447,6 +447,7 @@ def run_live(cfg, duration_s=None, capture_stub: bool = False) -> None:
     fsm = StateMachine(lockout_s=cfg.lockout_s)
     canary = Canary(cfg, pause_flag_path=Path("logs/pause.flag"))
     audit = AuditLog(Path("logs"))
+    detection_log = AuditLog(Path("logs/detections"))
     backends = [
         DiscordNotifier(cfg.discord.webhook_url),
         TelegramNotifier(cfg.telegram.bot_token, cfg.telegram.chat_id),
@@ -503,6 +504,18 @@ def run_live(cfg, duration_s=None, capture_stub: bool = False) -> None:
                 continue
             # detection
             res = detector.step(now)
+            detection_log.log({
+                "ts": now,
+                "event": "frame",
+                "window_found": res.window_found,
+                "dot_found": res.dot_found,
+                "rgb": list(res.rgb) if res.rgb is not None else None,
+                "match_name": res.match.name if res.match is not None else None,
+                "distance": round(res.match.distance, 2) if res.match is not None else None,
+                "confidence": round(res.match.confidence, 3) if res.match is not None else None,
+                "accepted": res.accepted,
+                "color": res.color,
+            })
             if res.accepted and res.color:
                 is_first = first_accepted
                 first_accepted = False
@@ -569,6 +582,7 @@ def run_live(cfg, duration_s=None, capture_stub: bool = False) -> None:
             pass
         notifier.stop()
         audit.close()
+        detection_log.close()
 
 
 def _build_capture(cfg, capture_stub: bool = False):