feat(audio-player): gear-menu default speed + split shortcuts into Mouse/Touch (plan §12)

The Player settings popover gains a 'Default playback speed' row
beside autoplay — a compact rate select, always visible (the Speed ▾
footer hides when current == default, which made the setting
undiscoverable at 1x/1×); same setDefaultSpeed PUT. The shortcuts
dialog splits its pointer section into MOUSE (click/drag/shift/wheel)
and TOUCH (drag/pull-away) — the bar has two scrub systems and the
sections now say so.

web/src/audio-keys.ts

@@ -215,22 +215,31 @@ export function visibleKeymap(): KeyActionSpec[] {
 
 // Pointer/wheel/touch interactions (plan §9) are not key events — the
 // dispatcher never sees them — but they belong in the same dialog so
-// every scrub gesture is discoverable in one place. templ x-fors this
-// table through the component's `pointerGuide` property (same binding
-// pattern as speeds/skipChoices).
+// every scrub gesture is discoverable in one place. TWO sections,
+// because the bar really does have two scrub systems (plan §12): the
+// desktop-pointer family and the touch family. templ x-fors these
+// through the component's `mouseGuide`/`touchGuide` properties (same
+// binding pattern as speeds/skipChoices).
 export interface PointerGuideRow {
   // Badge label, e.g. "Shift + drag".
   label: string;
   description: string;
 }
 
-export const POINTER_GUIDE: readonly PointerGuideRow[] = [
+export const MOUSE_GUIDE: readonly PointerGuideRow[] = [
   { label: "Click", description: "Seek — lands on a chapter line within a pixel's reach" },
   { label: "Drag", description: "Free scrub across the whole bar" },
   { label: "Shift + click", description: "Jump to the nearest chapter line" },
   { label: "Shift + drag", description: "Precision rail (±5 min) around the nearest line" },
   { label: "Wheel", description: "Nudge ±5s (Shift: ±60s)" },
-  { label: "Touch + pull away", description: "Scrub, then drag off the bar for fine control" },
+];
+
+export const TOUCH_GUIDE: readonly PointerGuideRow[] = [
+  { label: "Drag", description: "Free scrub across the whole bar" },
+  {
+    label: "Pull away",
+    description: "Drag off the bar while holding — the further you pull, the finer it gets",
+  },
 ];
 
 // resolveShortcut maps a keydown's (key, altKey) to an action, or null