feat: Universal Agent API Bridge & Modular Skill Engine Overhaul

- Add Gitea/Vikunja API sync scripts to eliminate prompt-pollution.
- Move submodules to .agent/vendor for proper CLI encapsulation.
- Implement extract_skills.js to dynamically flatten 19 active skills.
- Translate CLI skill descriptions to Korean.
- Mask .env.agent in .gitignore ensuring true Zero-Pollution secure template.

.agent/skills/ui-ux-pro-max/SKILL.md

@@ -1,6 +1,6 @@
 ---
 name: ui-ux-pro-max
-description: UI/UX design intelligence. 50 styles, 21 palettes, 50 font pairings, 20 charts, 9 stacks.
+description: UI/UX 디자인 AI. 50종의 스타일, 21종의 컬러 팔레트, 디자인 시스템 적용
 ---
 # ui-ux-pro-max