vibe code the initial impl

main/processing.h

@@ -0,0 +1,23 @@
+#pragma once
+#include <stdbool.h>
+#include <stdint.h>
+#include "esp_err.h"
+#include "detector.h"
+#include "feature_params.h"
+
+typedef struct {
+    uint32_t frames;
+    uint32_t proc_avg_us;     // exponential moving average of features+match time
+    uint32_t proc_max_us;
+    float last_rms, last_score;
+    bool last_match;
+    det_state_t state;
+    uint32_t triggers;
+    uint32_t last_trigger_s;  // uptime seconds of the last trigger, 0 = never
+} proc_stats_t;
+
+esp_err_t processing_start(void);
+void processing_get_stats(proc_stats_t *out);
+void processing_get_last_fp(float fp[NUM_BANDS]);
+void processing_set_monitor(bool on);
+bool processing_get_monitor(void);