feat(extract): emit WOM and WOB side-files (M2/WMO → open formats)

Extends asset_extract with two more open-format emitters:
  --emit-wom  foo.m2 (+ foo00.skin) → foo.wom
  --emit-wob  foo.wmo (+ foo_NNN.wmo groups) → foo.wob
  --emit-open now also turns these on

Originals are preserved so private servers still load .m2/.wmo
through the manifest path; the wowee runtime/editor pick up the
.wom/.wob next to them via the existing open-format search rules.

Implementation:
- New WoweeModelLoader::fromM2Bytes(m2Data, skinData) shares the
  conversion body with fromM2(path, am) via a static helper
  (convertM2ToWom). Lets the extractor convert without standing
  up an AssetManager.
- fromM2(path, am) moved to a separate translation unit
  (wowee_model_fromm2.cpp) so asset_extract doesn't have to
  link the AssetManager dependency.
- WoweeBuildingLoader::fromWMO already takes a WMOModel directly,
  so emitWobFromWmo just needs to read root + group files and
  call save().
- Group sub-files (<base>_NNN.wmo) are skipped during the walk
  since they're merged into the root WMO.

tools/asset_extract/extractor.cpp

@@ -979,10 +979,11 @@ bool Extractor::run(const Options& opts) {
     // Open-format emission: walk the extracted tree and write
     // wowee-format side-files (PNG / JSON DBC) next to each .blp/.dbc.
     // Originals are left untouched so private servers continue to work.
-    if (opts.emitPng || opts.emitJsonDbc) {
+    if (opts.emitPng || opts.emitJsonDbc || opts.emitWom || opts.emitWob) {
         std::cout << "Emitting wowee open-format side-files...\n";
         OpenFormatStats ofs;
-        emitOpenFormats(effectiveOutputDir, opts.emitPng, opts.emitJsonDbc, ofs);
+        emitOpenFormats(effectiveOutputDir, opts.emitPng, opts.emitJsonDbc,
+                        opts.emitWom, opts.emitWob, ofs);
         if (opts.emitPng) {
             std::cout << "  PNG (BLP→PNG)     : " << ofs.pngOk << " ok";
             if (ofs.pngFail) std::cout << ", " << ofs.pngFail << " failed";
@@ -993,6 +994,16 @@ bool Extractor::run(const Options& opts) {
             if (ofs.jsonDbcFail) std::cout << ", " << ofs.jsonDbcFail << " failed";
             std::cout << "\n";
         }
+        if (opts.emitWom) {
+            std::cout << "  WOM (M2→WOM)      : " << ofs.womOk << " ok";
+            if (ofs.womFail) std::cout << ", " << ofs.womFail << " failed";
+            std::cout << "\n";
+        }
+        if (opts.emitWob) {
+            std::cout << "  WOB (WMO→WOB)     : " << ofs.wobOk << " ok";
+            if (ofs.wobFail) std::cout << ", " << ofs.wobFail << " failed";
+            std::cout << "\n";
+        }
     }
 
     // Cache WoW.exe for Warden MEM_CHECK responses