feat(editor): add --catalog-stats for single-file deep size analysis

Reports header bytes (magic + version + nameLen + name +
entryCount) vs entry-section bytes, average entry size, total
file size, the catalog's name string length, and the first
entry's id field. Useful for sizing analysis: "which catalogs
are biggest, where do the bytes go, what's the per-entry
overhead".

Goes deeper than --info-magic which just reports the magic +
version + name + count. The byte breakdown distinguishes:
  - headerBytes        — fixed-cost header
  - catalogNameBytes   — variable-length catalog label
  - entrySectionBytes  — total size of all entries combined
  - averageEntryBytes  — entrySectionBytes / entryCount

Only the first entry's id is sampled because entries have
variable-length name+description strings — multi-sampling
produces garbage for most formats. The single sampled id is
reliable because it sits at exactly headerBytes offset.

JSON sidecar via --json. Format metadata (description / category)
is included from the format table when the magic is recognized;
unknown magics still get the size breakdown but no metadata.

This is the 18th cross-format utility; the second per-file
single-target one (alongside --info-magic). CLI flag count
1033 -> 1034.

tools/editor/cli_arg_required.cpp

@@ -140,6 +140,7 @@ const char* const kArgRequired[] = {
     "--magic-fix", "--bulk-validate",
     "--bulk-export-json", "--bulk-import-json",
     "--diff-tree", "--orphan-jsons", "--list-by-magic",
+    "--catalog-stats",
     "--gen-animations", "--gen-animations-combat", "--gen-animations-movement",
     "--info-wani", "--validate-wani",
     "--export-wani-json", "--import-wani-json",