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

src/pxl8_atlas.h

@@ -1,35 +0,0 @@
-#pragma once
-
-#include "pxl8_types.h"
-
-typedef struct pxl8_atlas pxl8_atlas;
-
-typedef struct pxl8_atlas_entry {
-    bool active;
-    u32 texture_id;
-    i32 x, y, w, h;
-} pxl8_atlas_entry;
-
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-pxl8_atlas* pxl8_atlas_create(u32 width, u32 height, pxl8_pixel_mode pixel_mode);
-void pxl8_atlas_destroy(pxl8_atlas* atlas);
-
-const pxl8_atlas_entry* pxl8_atlas_get_entry(const pxl8_atlas* atlas, u32 id);
-u32 pxl8_atlas_get_entry_count(const pxl8_atlas* atlas);
-u32 pxl8_atlas_get_height(const pxl8_atlas* atlas);
-const u8* pxl8_atlas_get_pixels(const pxl8_atlas* atlas);
-u32 pxl8_atlas_get_width(const pxl8_atlas* atlas);
-bool pxl8_atlas_is_dirty(const pxl8_atlas* atlas);
-
-void pxl8_atlas_mark_clean(pxl8_atlas* atlas);
-
-u32 pxl8_atlas_add_texture(pxl8_atlas* atlas, const u8* pixels, u32 w, u32 h, pxl8_pixel_mode pixel_mode);
-void pxl8_atlas_clear(pxl8_atlas* atlas, u32 preserve_count);
-bool pxl8_atlas_expand(pxl8_atlas* atlas, pxl8_pixel_mode pixel_mode);
-
-#ifdef __cplusplus
-}
-#endif