Reorganized the code structure, fix a lot of issues.

CLAUDE.md

@@ -9,6 +9,7 @@ A browser-based world map creation tool (like Wonderdraft/Inkarnate). C99 compil
 - **UI:** Dear ImGui via cimgui — `lib/imgui/`
 - **Math:** cglm (types are C arrays: `vec2` = `float[2]`, `mat4` = `float[4][4]` column-major) — `lib/cglm/`
 - **Shaders:** WGSL in `src/shaders/`, compiled to C headers via `xxd -i` into `src/generated/`
+- **Shapes:** Line-strip based vector shapes (circle, star) with procedural vertex generation
 
 ### Build
 - `make` (release) / `make debug` — outputs `app.html`
@@ -16,9 +17,13 @@ A browser-based world map creation tool (like Wonderdraft/Inkarnate). C99 compil
 - Include paths: `lib/sokol`, `lib/imgui`, `lib/imgui/imgui`, `lib/util`, `lib/cglm/include`
 
 ### Key files
-- `src/main.c` — entry point, sokol init, render loop, input (zoom/pan/drag)
-- `src/api.h` — central include hub, backend defines
-- `src/sprite.h` — sprite batching, texture manager, file import stubs
+- `src/main.c` — entry point, sokol init, render loop, all input handling, overlay geometry, UI panels, and debug stats
+- `src/api.h` — central include hub, backend defines, ALLOC/FREE macros (wired to smemtrack)
+- `src/camera.h` — viewport state (zoom/pan), MVP matrix computation, screen↔world coordinate transforms
+- `src/render.h` — shape pipeline init/shutdown, per-shape draw calls (shader uniform binding)
+- `src/shape.h` — shape geometry types, procedural generation (circle/star), transform building, hit testing, buffer management
+- `src/spatial.h` — spatial hash grid for accelerating hit tests and rect-selection queries
+- `src/history.h` — undo/redo stack with property-level tracking (position/scale/rotation/color), edit session capture, batch operations
 - `src/util.h` — `vector_t` (dynamic array) and `mem_pool_t` (free-list pool), both stripe-based
 - `src/rand.h` — xorshift32 PRNG