tune: calibrate speed presets from through-air mic test (unit floor ~120ms)

Mic+speaker calibration (tools/calibrate_audio.py): unit=120/160 decode 18/18;
90/70 fail because dahGap (2*unit) falls under the detector's ~200ms reverb
window. Presets: brisk=120 (proven floor), normal=150, relaxed=190.

lib/timing.js

@@ -49,11 +49,21 @@ export function makeTiming(unitMs = 120) {
     });
 }
 
-/** Named speed presets (unit in ms). Smaller = faster. */
+/**
+ * Named speed presets (unit in ms). Smaller = faster.
+ *
+ * Floor calibrated through-air on a MacBook (tools/calibrate_audio.py,
+ * 2026-06-01): unit=120 decoded 18/18, unit=90 failed because a dash's two
+ * taps (2×unit = 180 ms) dropped below the detector's ~200 ms reverb-rejection
+ * window and merged into one. So `dahGap = 2×unit` must stay comfortably above
+ * ~200 ms → keep unit ≳ 120. `brisk` is pinned to that proven floor; `normal`
+ * and `relaxed` add margin since the robot's antenna clicks reverberate more
+ * than a speaker blip.
+ */
 export const SPEED_PRESETS = Object.freeze({
-    relaxed: 160,
-    normal: 120,
-    brisk: 90,
+    relaxed: 190,
+    normal: 150,
+    brisk: 120,
 });
 
 export const DEFAULT_TIMING = makeTiming(SPEED_PRESETS.normal);

lib/version.js

@@ -1,3 +1,3 @@
 // Deployment version label, shown in Settings so you can verify which build
 // is actually loaded after a push. Format: "YYYY-MM-DD rN", bumped on push.
-export const APP_VERSION = "2026-06-01 r1 initial";
+export const APP_VERSION = "2026-06-01 r2 audio-calibrated";