refactor: reorganize pxl8 into client/src/ module structure

- core/: main entry, types, logging, I/O, RNG
- asset/: ase loader, cart, save, embed
- gfx/: graphics, animation, atlas, fonts, tilemap, transitions
- sfx/: audio
- script/: lua/fennel runtime, REPL
- hal/: platform abstraction (SDL3)
- world/: BSP, world, procedural gen
- math/: math utilities
- game/: GUI, replay
- lua/: Lua API modules

demo/mod/music.fnl

@@ -64,16 +64,16 @@
 (local step-duration sixteenth)
 
 (fn init []
-  (set ctx (pxl8.sfx_context_create))
+  (set ctx (pxl8.create_sfx_context))
 
-  (local reverb (pxl8.sfx_reverb_create
+  (local reverb (pxl8.create_reverb
     {:room 0.5 :damping 0.4 :mix 0.35}))
-  (local compressor (pxl8.sfx_compressor_create
+  (local compressor (pxl8.create_compressor
     {:threshold -18 :ratio 6 :attack 3 :release 100}))
-  (pxl8.sfx_context_append_node ctx reverb)
-  (pxl8.sfx_context_append_node ctx compressor)
+  (ctx:append_node reverb)
+  (ctx:append_node compressor)
 
-  (pxl8.sfx_mixer_attach ctx)
+  (ctx:attach)
 
   (set melody-params (pxl8.sfx_voice_params
     {:waveform pxl8.SFX_WAVE_TRIANGLE
@@ -96,7 +96,7 @@
 
 (fn stop []
   (set playing false)
-  (pxl8.sfx_stop_all ctx))
+  (ctx:stop_all))
 
 (fn update [dt]
   (when playing
@@ -109,7 +109,7 @@
       (local melody-note (. melody-entry 1))
       (local melody-dur (. melody-entry 2))
       (when (> melody-note 0)
-        (pxl8.sfx_play_note ctx melody-note melody-params 0.45 melody-dur))
+        (ctx:play_note melody-note melody-params 0.45 melody-dur))
 
       (local bass-step (math.floor (/ step 2)))
       (local bass-idx (+ 1 (% bass-step (length bass))))
@@ -117,7 +117,7 @@
       (local bass-note (. bass-entry 1))
       (local bass-dur (. bass-entry 2))
       (when (= (% step 2) 0)
-        (pxl8.sfx_play_note ctx bass-note bass-params 0.55 bass-dur))
+        (ctx:play_note bass-note bass-params 0.55 bass-dur))
 
       (set step (+ step 1)))))