Replaces display-name prefix parsing ([RTF]/[RTFC]/[RTFR]) with
Discord role-based clan detection (TEAI/TEAF/TEAC/TEACO).
- config: new CLAN_CONFIG with 4 TEA clans, CLAN_ROLE_IDS, CLAN_MIGRATION
- helpers: get_user_clan() replaced by get_clan_from_member()
- DatabaseManager: adds clan column on startup, auto-migrates existing
records from old username prefixes, filters leaderboard by clan column
- pb_handler: detects clan from roles on submission, passes it to DB
- leaderboard_handler: reads clan from DB column instead of username
- top10: new commands !teai*/!teaf*/!teac*/!teaco* (removes !rtf*)
- guide: updated command list and bot title
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
