feat: Add BetterChat + TimedExecute plugin config modules

- DB migrations 017 (betterchat_configs) and 020 (timedexecute_configs) applied
- TypeORM entities matching production schema exactly
- NestJS modules with full CRUD + apply-to-server + import-from-server
- Pinia stores following teleport config pattern
- BetterChatView: Chat Groups editor with color pickers, font sizes, format strings; Settings tab with word filter, anti-flood, player tagging
- TimedExecuteView: TimerRepeat with presets, RealTime-Timer, OnConnect/OnDisconnect command lists
- Wired into app.module.ts, router, DashboardLayout nav

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

backend-nest/src/app.module.ts

@@ -41,6 +41,8 @@ import { GatherModule } from './modules/gather/gather.module';
 import { AutoDoorsModule } from './modules/autodoors/autodoors.module';
 import { KitsModule } from './modules/kits/kits.module';
 import { FurnaceSplitterModule } from './modules/furnacesplitter/furnacesplitter.module';
+import { BetterChatModule } from './modules/betterchat/betterchat.module';
+import { TimedExecuteModule } from './modules/timedexecute/timedexecute.module';
 
 // Shared Services
 import { NatsService } from './services/nats.service';
@@ -117,6 +119,8 @@ import { NatsBridgeGateway } from './gateways/nats-bridge.gateway';
     AutoDoorsModule,
     KitsModule,
     FurnaceSplitterModule,
+    BetterChatModule,
+    TimedExecuteModule,
   ],
   providers: [
     // Global guards (order matters: auth first, then license, then permissions)