Normalize OneBot WS role values to canonical PascalCase ('Api'|'Event'|'Universal') across core and web UI, and support auto-migration from legacy lowercase on-disk values. Updated types, defaults, serializers/parsers, and runtime checks in ws-transport, adjusted WebUI select options and default entries, and updated the client User-Agent string. Added a test to verify that legacy lowercase role values are migrated to the new canonical form on load.