chore: restructure skills repo with new agents and skill bundles

- Add new skills: deep-dive, docs-rag, meta-creator, ppt-maker, sdlc
- Add agent configs: g-assistent, meta-creator, sdlc with prompt files
- Add reference docs for custom agents and skills specification
- Add utility scripts: install-agents.sh, orchestrate.py, puml2svg.sh
- Update README and commit-message skill config
- Remove deprecated skills: codereview, python, testing, typescript
- Add .gitignore

.kiro/agents/sdlc.json

@@ -0,0 +1,11 @@
+{
+  "name": "sdlc",
+  "description": "Systematic SDLC assistant. Guides through requirements analysis, system design, task decomposition, and implementation planning for any software project.",
+  "prompt": "file://prompts/sdlc.md",
+  "tools": ["fs_read", "fs_write", "execute_bash", "grep", "glob"],
+  "allowedTools": ["fs_read", "grep", "glob"],
+  "resources": [
+    "skill://.kiro/skills/sdlc/SKILL.md",
+    "file://.kiro/skills/sdlc/assets/phase-checklist.md"
+  ]
+}