feat(editor): add --tree-summary-md content inventory generator

Walks a directory recursively, identifies every Wowee
open-format file by 4-byte magic, parses the standard
catalog header, and emits a Markdown report. Useful for
content-bundle distributions to ship with a README of
what's inside, and for change-log generation when
diffing two content snapshots manually.

The report has three sections: a summary table (total
files / recognized / bytes), a per-format breakdown
(magic / ext / file count / total entries / description),
and a per-file detail table (path / magic / version /
catalog name / entries / bytes). Output to stdout if no
out path is given, otherwise written to a file.

Reuses cli_format_table.cpp so any new format added in
the future appears automatically without touching this
tool.

tools/editor/cli_arg_required.cpp

@@ -135,7 +135,7 @@ const char* const kArgRequired[] = {
     "--info-wliq", "--validate-wliq",
     "--export-wliq-json", "--import-wliq-json",
     "--info-magic", "--summary-dir", "--rename-by-magic",
-    "--bulk-rename-by-magic", "--touch-tree",
+    "--bulk-rename-by-magic", "--touch-tree", "--tree-summary-md",
     "--gen-animations", "--gen-animations-combat", "--gen-animations-movement",
     "--info-wani", "--validate-wani",
     "--export-wani-json", "--import-wani-json",