Add module control API, bigcursor with fractional scaling, shared mutex

Module control API:
- Three cdecl exports: WeirdUtils_IsModuleActive, WeirdUtils_DisableModule, WeirdUtils_DisableAll
- C header include/weirdutils_api.h for runtime DLL discovery
- All modules gain pub module_name, isActive(), shared mutex via src/mutex.zig
- build.zig refactored to module_list array of ModuleDesc

Bigcursor:
- D3D9 vtable hooks on SetCursorProperties/ShowCursor
- Scale2x/Scale3x pixel-art upscalers in pure Zig (replaces 12K-line hqx C)
- Bilinear resampler for fractional scales (1.0-4.0, default 1.2)
- Win32 cursor via CreateIconIndirect bypasses D3D9 32x32 limit
- FNV-1a hash cache for ~16 cursor bitmaps
- Lua API: SetCursorScale(n) / GetCursorScale()
- CVar cursorScale for Config.wtf persistence (tenths)

Other:
- Add dpslog module stub
- Docs and README updates

DLL_README.md

@@ -97,7 +97,7 @@ Enables loading loose game asset files (models, textures, etc.) from the `Data/`
 
 Also allows multi-character patch archive names (e.g. `patch-12.mpq`, `patch-jimbo.mpq`).
 
-Patch archives are sorted case-insensitively by filename — last in the sort gets highest priority, and all patches override the base archives.
+Patch archives are sorted case-insensitively by filename - last in the sort gets highest priority, and all patches override the base archives.
 
 No configuration needed, install and forget.
 
@@ -139,7 +139,12 @@ Fixes duplicate floating heal numbers caused by SuperWoW 1.5. Only relevant if y
 
 ### Big Cursor
 
-Increases the hardware cursor render size for improved visibility. No configuration needed, install and forget.
+Upscales the hardware cursor for improved visibility without losing sharpness. Supports fractional scales from 1.0 (off) to 4.0.
+
+- `/script SetCursorScale(1.2)` -- set cursor scale (default 1.2x)
+- `/script SetCursorScale(1)` -- disable (use original 32x32 cursor)
+
+This value is saved to the `cursorScale` CVar in tenths: `/script SetCVar("cursorScale", "15")` for 1.5x.
 
 **DLL:** `bigcursor.dll`
 
@@ -152,3 +157,60 @@ This project is distributed as pre-built DLLs only. The source code is not and w
 These DLLs work by hooking deeply into the game client's internals: memory layout, function addresses, rendering pipeline, input handling, and more.  
 While every feature here is built for legitimate quality-of-life use, the underlying techniques touch on too many core mechanisms that are trivially abusable.  
 Publishing the source would be handing a candy store to bad actors: the same hooks and patterns used to render a raid marker or fix a crash can be repurposed for cheats, exploits, and in particular automation with minimal effort.
+
+---
+
+## Developer Notes
+### Runtime Module Control API
+
+WeirdUtils exports three functions for querying and disabling modules at runtime. This is the preferred way for other DLLs to check module state and take over functionality - no mutex tricks needed.
+
+#### Exported Functions
+
+| Function | Signature | Description |
+|---|---|---|
+| `WeirdUtils_IsModuleActive` | `int __cdecl (const char *name)` | Returns 1 if the module is compiled in and currently hooked, 0 otherwise |
+| `WeirdUtils_DisableModule` | `int __cdecl (const char *name)` | Unhooks the named module. Returns 1 if found, 0 otherwise |
+| `WeirdUtils_DisableAll` | `int __cdecl (void)` | Unhooks all modules and core hooks. Returns count of modules disabled |
+
+Module names are case-insensitive and match the build option names:
+
+`customassets`, `framecrash`, `logsessions`, `transmogfix`, `minimapicons`, `healtextfix`, `bigcursor`, `worldmarkers`, `interact`, `outline`, `screenshot`
+
+There is no re-enable API - re-hooking after unhook is unsafe.
+
+#### C/C++ Header
+
+A header-only `include/weirdutils_api.h` is provided that handles DLL discovery and runtime resolution automatically. No .lib file needed:
+
+```c
+#include "weirdutils_api.h"
+
+// Returns 0 if WeirdUtils isn't loaded - safe to call unconditionally
+if (WeirdUtils_IsModuleActive("transmogfix"))
+    WeirdUtils_DisableModule("transmogfix");
+```
+
+The header tries all known DLL names (`weirdutils.dll`, `worldmarkers.dll`, etc.) via `GetModuleHandleA`, so it works regardless of which DLL variant is loaded.
+
+#### Raw GetProcAddress
+
+If you prefer not to use the header:
+
+```c
+HMODULE hMod = GetModuleHandleA("weirdutils.dll");
+if (hMod) {
+    typedef int (__cdecl *IsActiveFn)(const char *);
+    IsActiveFn isActive = (IsActiveFn)GetProcAddress(hMod, "WeirdUtils_IsModuleActive");
+    if (isActive && isActive("transmogfix")) {
+        typedef int (__cdecl *DisableFn)(const char *);
+        DisableFn disable = (DisableFn)GetProcAddress(hMod, "WeirdUtils_DisableModule");
+        if (disable) disable("transmogfix");
+    }
+}
+
+### Module Mutexes
+
+Each module holds a named mutex while active: `Local\WeirdUtils_<name>_<PID>` (e.g. `Local\WeirdUtils_framecrash_12345`). The exception is transmogfix, which uses `Local\TransmogCoalesceHook_<PID>` for legacy reasons.
+
+If you see the mutex, the module is loaded - use the Runtime Module Control API below to disable it. If you don't see it, the module isn't active and you're free to hook those functions yourself.