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/nest-cli.json

@@ -0,0 +1,5 @@
+{
+	"$schema": "https://json-schema.org/nest-cli",
+	"collection": "@nestjs/schematics",
+	"sourceRoot": "src"
+}