feat(editor): add WWFL JSON round-trip (--export/--import-wwfl-json)

Dual encoding for both WWFL enums via the readEnumField
template: filterKind (int 0..5 OR 255 OR token "spam"/
"goldseller"/"allcaps"/"repeatchar"/"url"/"advertreward"/
"misc") and severity (int 0..3 OR token "warn"/"replace"/
"drop"/"mute"). caseSensitive accepts bool or int.

pattern and replacement serialize as plain JSON strings —
operators editing the JSON sidecar can hand-craft new
moderation patterns without binary tooling. Strings are
nlohmann::json-escaped on export and unescaped on import,
preserving literal special characters byte-identically.

All 3 presets (spam/caps/url) byte-identical roundtrip
OK. CLI flag count 1239 -> 1241.

tools/editor/cli_arg_required.cpp

@@ -358,6 +358,7 @@ const char* const kArgRequired[] = {
     "--export-wtrd-json", "--import-wtrd-json",
     "--gen-wfl", "--gen-wfl-caps", "--gen-wfl-url",
     "--info-wwfl", "--validate-wwfl",
+    "--export-wwfl-json", "--import-wwfl-json",
     "--gen-weather-temperate", "--gen-weather-arctic",
     "--gen-weather-desert", "--gen-weather-stormy",
     "--gen-zone-atmosphere",