Enhance buzzer detection logic to group intermittent matches with a 500 ms quiet tail, updating relevant configurations and documentation.

main/detector.h

@@ -14,7 +14,11 @@ typedef struct {
 typedef struct {
     det_state_t state;
     uint32_t hist;          // bit 0 = newest frame, 1 = matched
-    uint32_t cooldown_start_ms;
+    uint32_t frame_index;
+    uint32_t match_time_ms[32];
+    uint32_t buzz_start_ms;
+    uint32_t last_match_ms;
+    uint32_t last_completed_start_ms;
     uint32_t triggers;
 } detector_t;
 
@@ -24,8 +28,9 @@ void detector_reset(detector_t *d);     // back to IDLE with empty history
 // Loudness gate AND score >= threshold.
 bool detector_is_match(float rms, float score, float min_rms, float threshold);
 
-// Feed one frame. Returns true exactly once per trigger (IDLE -> TRIGGERED).
-// TRIGGERED lasts one frame, then COOLDOWN until cooldown_ms elapsed, then IDLE
-// with a cleared history (the buzzer's tail cannot re-trigger).
-bool detector_update(detector_t *d, bool match, uint32_t now_ms, const detector_cfg_t *cfg);
+// Feed one frame. Returns true when a buzz event ends and writes its duration.
+// Matches within cooldown_ms extend the same event; the final quiet tail is
+// excluded from its duration.
+bool detector_update(detector_t *d, bool match, uint32_t now_ms, const detector_cfg_t *cfg,
+                     uint32_t *buzz_duration_ms);
 const char *detector_state_name(det_state_t s);