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

src/minimapicons/minimapicons.zig

@@ -8,48 +8,30 @@
 //!
 //! TODO: Hook minimap icon rendering, classify NPCs by type, overlay custom icons.
 
-const std = @import("std");
 const con = @import("../console.zig");
+const mod_mutex = @import("../mutex.zig");
 
-const WINAPI = std.builtin.CallingConvention.winapi;
-extern "kernel32" fn CreateMutexA(lpMutexAttributes: ?*anyopaque, bInitialOwner: i32, lpName: [*:0]const u8) callconv(WINAPI) ?*anyopaque;
-extern "kernel32" fn ReleaseMutex(hMutex: *anyopaque) callconv(WINAPI) i32;
-extern "kernel32" fn CloseHandle(hObject: *anyopaque) callconv(WINAPI) i32;
-extern "kernel32" fn GetLastError() callconv(WINAPI) u32;
-extern "kernel32" fn GetCurrentProcessId() callconv(WINAPI) u32;
-const ERROR_ALREADY_EXISTS: u32 = 183;
+pub const module_name: [*:0]const u8 = "minimapicons";
 
 var g_mutex: ?*anyopaque = null;
 var g_is_hook_owner: bool = false;
 
+pub fn isActive() bool {
+    return g_is_hook_owner;
+}
+
 pub fn installHooks() void {
     con.print("[minimapicons] Module loaded (stub)\n");
 
-    // Multi-DLL safety: only one instance per process should hook
-    var mutex_name_buf: [64]u8 = undefined;
-    const mutex_name = std.fmt.bufPrint(&mutex_name_buf, "Local\\WeirdUtils_MinimapiconsHook_{d}", .{GetCurrentProcessId()}) catch return;
-    mutex_name_buf[mutex_name.len] = 0;
-
-    g_mutex = CreateMutexA(null, 1, @ptrCast(mutex_name_buf[0..mutex_name.len :0]));
-    if (g_mutex == null) return;
-
-    if (GetLastError() == ERROR_ALREADY_EXISTS) {
-        _ = CloseHandle(g_mutex.?);
-        g_mutex = null;
-        g_is_hook_owner = false;
-        con.print("[minimapicons] Another DLL owns hooks (mutex taken), skipping\n");
-        return;
-    }
-    g_is_hook_owner = true;
+    const result = mod_mutex.acquire(module_name);
+    g_mutex = result.handle;
+    g_is_hook_owner = result.is_owner;
+    if (!g_is_hook_owner) return;
 }
 
 pub fn removeHooks() void {
     if (g_is_hook_owner) {
-        if (g_mutex) |m| {
-            _ = ReleaseMutex(m);
-            _ = CloseHandle(m);
-            g_mutex = null;
-        }
+        mod_mutex.release(&g_mutex);
     }
     g_is_hook_owner = false;
 }