feat(matrix-skilltree-bot): add Matrix bot for skill tree and XP management

- Skill management: create, list, view details, delete
- XP tracking with level-up notifications
- Branch filtering (intellect, body, creativity, social, practical, mindset, custom)
- Activity history per skill or global
- User statistics (total XP, skill count, highest level, streak)
- German/English command aliases
- Number-based reference system for ease of use
- JWT auth via mana-core-auth
- Health check endpoint on port 3326

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

services/matrix-skilltree-bot/src/skilltree/skilltree.module.ts

@@ -0,0 +1,8 @@
+import { Module } from '@nestjs/common';
+import { SkilltreeService } from './skilltree.service';
+
+@Module({
+	providers: [SkilltreeService],
+	exports: [SkilltreeService],
+})
+export class SkilltreeModule {}