Refactor GameAudio from the single clear cue into a full bank: load swap,
match, combo1..combo5, win, lose once at startup, each into its own
SystemSoundID via load_system_sound. Expose per-event play methods
(play_swap/play_match/play_cascade/play_win/play_lose), each a single
AudioServicesPlaySystemSound. play_cascade selects the ascending clip by
clamping cascade depth through the pure, OS-agnostic cascade_cue_index
(depth<=1 -> combo1, depth>=5 -> combo5) so P10.4 can snapshot it headlessly.
Layer stays purely additive and inline-if-OS==.ios guarded; the clear trigger
is migrated to sfx_cascade(mv.rounds.len) at its board_view call site, with
sfx_swap/match/win/lose shims staged for P10.3 wiring. No framework added
beyond the already-linked AudioToolbox/CoreFoundation (build.sx untouched).
Feasibility spike outcome: iOS audio from sx is feasible with no sx-library
change. System Sound Services is plain C, reached with the same `#foreign`
FFI uikit.sx already uses (UIApplicationMain / dlsym / CACurrentMediaTime);
AudioToolbox + CoreFoundation are linked per-target in build.sx.
Smallest viable SFX: one short CC0 clip (Kenney Interface Sounds, CC0 1.0)
played when a swap clears a match. Purely additive — audio.sx reads/writes
no score/board/move state; the wiring in board_view only adds a call.
- audio.sx: load clear.wav once, AudioServicesPlaySystemSound on clear
- board_view.sx: trigger sfx_clear() on a legal swap that clears (>=1 round)
- main.sx: allocate + init g_audio at boot
- build.sx: link AudioToolbox + CoreFoundation on iOS
- assets/audio/clear.wav (+ one-line CC0 credit in LICENSE.txt)
Verified: ios-sim build links; 18/18 tests pass; sim boot log shows
"[sx] audio: clear cue loaded" (AudioServicesCreateSystemSoundID succeeded,
asset shipped in the bundle and decoded).
