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/dpslog/dpslog.zig

@@ -0,0 +1,34 @@
+//! DPS log module.
+//!
+//! Provides structured Lua objects for combat log events so addons can read
+//! parsed fields directly instead of re-parsing the combat log string.
+//!
+//! TODO: Hook combat log event dispatch, build Lua tables per event type.
+
+const con = @import("../console.zig");
+const mod_mutex = @import("../mutex.zig");
+
+pub const module_name: [*:0]const u8 = "dpslog";
+
+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("[dpslog] Module loaded (stub)\n");
+
+    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) {
+        mod_mutex.release(&g_mutex);
+    }
+    g_is_hook_owner = false;
+}