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

skills/ppt-maker/_meta.json

@@ -0,0 +1,6 @@
+{
+  "ownerId": "kn75v9attg6retx4mdm14beva983desk",
+  "slug": "ppt-maker",
+  "version": "1.0.3",
+  "publishedAt": 1774166054605
+}