refactor(editor): extract data-tree audit/migration into cli_data_tree.cpp

Moves the seven proprietary-data-tree handlers out of main.cpp:
  --migrate-data-tree         --bench-migrate-data-tree
  --list-data-tree-largest    --export-data-tree-md
  --info-data-tree            --strip-data-tree
  --audit-data-tree

All operate on a Blizzard-format extracted Data tree (the .m2/
.skin/.wmo/.blp/.dbc files) — they audit, migrate, or strip
proprietary-format files in support of the open-format
migration story.

Original placement spanned two sub-blocks (12546-12892 and
13093-13417 in main.cpp) interrupted by --gen-texture and
--add-texture-to-zone in the middle. Extraction collapses
both sub-blocks into one cohesive translation unit.

main.cpp drops 16,321 → 15,653 lines (-668). Behavior verified
by re-running --info-data-tree against a missing directory.

tools/editor/cli_data_tree.hpp

@@ -0,0 +1,21 @@
+#pragma once
+
+namespace wowee {
+namespace editor {
+namespace cli {
+
+// Dispatch the proprietary-data-tree audit + migration handlers:
+//   --migrate-data-tree         --bench-migrate-data-tree
+//   --list-data-tree-largest    --export-data-tree-md
+//   --info-data-tree            --strip-data-tree
+//   --audit-data-tree
+//
+// All operate on a Blizzard-format extracted Data tree
+// (the .m2/.skin/.wmo/.blp/.dbc files).
+//
+// Returns true if matched; outRc holds the exit code.
+bool handleDataTree(int& i, int argc, char** argv, int& outRc);
+
+} // namespace cli
+} // namespace editor
+} // namespace wowee