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/commit-message/assets/architecture.puml

@@ -0,0 +1,24 @@
+@startuml commit-message-architecture
+skinparam componentStyle rectangle
+skinparam defaultFontName Arial
+skinparam backgroundColor #FAFAFA
+
+package "commit-message Skill" {
+  component "SKILL.md\n(instructions)" as SKILL
+  component "references/\nconventional-commits.md" as REF
+  component "evals/evals.json" as EVALS
+}
+
+package "Git Environment" {
+  database "Staged Changes\n(git index)" as INDEX
+  component "git commit" as GIT
+}
+
+actor Developer
+
+Developer --> SKILL : triggers skill
+SKILL --> REF : loads commit format rules
+SKILL --> INDEX : reads via git diff --cached
+SKILL --> Developer : proposes message
+Developer --> GIT : confirms & commits
+@enduml