chore: quantlab-agent 프로젝트 초기 설정

agent_guide 템플릿 기반으로 프로젝트 구조 설정.
Gitea(quantlab-agent), Vikunja(project #15) 연동 완료.

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

.agent/skills/gsd-join-discord/SKILL.md

@@ -0,0 +1,19 @@
+---
+name: gsd-join-discord
+description: Join the GSD Discord community
+---
+
+
+<objective>
+Display the Discord invite link for the GSD community server.
+</objective>
+
+<output>
+# Join the GSD Discord
+
+Connect with other GSD users, get help, share what you're building, and stay updated.
+
+**Invite link:** https://discord.gg/gsd
+
+Click the link or paste it into your browser to join.
+</output>