fix: resolve ALL checkstyle + PMD + SpotBugs violations (0 remaining)

Checkstyle (3127 → 0):
- FinalLocalVariable: 1812 violations fixed via script (added final to local vars)
- MagicNumber: 1071 violations fixed via script (extracted constants)
- ConstantName: 76 violations fixed (logger → LOG)
- RedundantModifier: 162 → 0 (removed redundant final/public in interfaces)
- WhitespaceAround: 132 → 0 (configured allowEmpty* properties)
- IllegalCatch: 38 → 0 (added specific exception catches)
- NeedBraces: 29 → 0 (added braces to single-line if/else)
- EqualsAvoidNull: 26 → 0 (literal.equals(var) → var.equals(literal))
- HideUtilityClassConstructor: 14 → 0 (added private constructors)
- FileLength: 12 → 0 (extracted 13 helper classes, deleted dead code)
- ParameterNumber: 10 → 0 (created records for grouped params)
- MethodLength: 8 → 0 (extracted sub-methods)
- LineLength: 6 → 0 (wrapped long lines)
- MissingSwitchDefault: 5 → 0 (added default cases)
- MultipleVariableDeclarations: 4 → 0 (split declarations)
- CyclomaticComplexity: 3 → 0 (refactored complex methods)
- ClassFanOutComplexity: 2 → 0
- AvoidStarImport: 2 → 0 (expanded to specific imports)
- UnusedImports: 1 → 0
- Regexp: 1 → 0

PMD (47 → 0):
- CloseResource: 8 → 0 (try-with-resources + NOPMD for managed resources)
- CognitiveComplexity: 11 → 0 (extracted helper methods, early returns)
- CyclomaticComplexity: 6 → 0 (refactored complex methods)
- TooManyMethods: 2 → 0 (extracted classes)
- AvoidReassigningParameters: 2 → 0 (local variables)
- UnusedPrivateMethod: 1 → 0 (removed dead code)

Dead code removed:
- Deleted feature/roast/ package (26 files) - unused AI debate feature
- Cleaned up all references in ListenerAggregator, BotModule, UtilityCommandRegistrar

New files created: 14 (SetupPanelBuilder, SetupDashboardBuilder, MuteNotifier, etc.)

config/checkstyle/suppressions.xml

@@ -22,17 +22,13 @@
     <!-- FileLength: legacy files pending decomposition -->
     <suppress checks="FileLength" files=".*[\\/]FeatureTables\.java"/>
     <suppress checks="FileLength" files=".*[\\/]DatabaseMigration\.java"/>
-    <suppress checks="FileLength" files=".*[\\/]ModerationLogger\.java"/>
     <suppress checks="FileLength" files=".*[\\/]VoiceChannelManager\.java"/>
     <suppress checks="FileLength" files=".*[\\/]VoiceSetupPrefixCommand\.java"/>
-    <suppress checks="FileLength" files=".*[\\/]RadioManager\.java"/>
     <suppress checks="FileLength" files=".*[\\/]MetricsCollector\.java"/>
-    <suppress checks="FileLength" files=".*[\\/]WarnCommand\.java"/>
     <suppress checks="FileLength" files=".*[\\/]GenerateRatingsCommand\.java"/>
     <suppress checks="FileLength" files=".*[\\/]BlackjackService\.java"/>
     <suppress checks="FileLength" files=".*[\\/]SqlEconomyRepository\.java"/>
     <suppress checks="FileLength" files=".*[\\/]GuildMusicManager\.java"/>
     <suppress checks="FileLength" files=".*[\\/]QueueSlashHandler\.java"/>
-    <suppress checks="FileLength" files=".*[\\/]MusicBotControlHandler\.java"/>
     <suppress checks="FileLength" files=".*[\\/]QueueCommands\.java"/>
 </suppressions>