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/sdlc/assets/architecture.puml

@@ -0,0 +1,38 @@
+@startuml sdlc-architecture
+skinparam componentStyle rectangle
+skinparam defaultFontName Arial
+skinparam backgroundColor #FAFAFA
+
+package "sdlc Skill" {
+  component "SKILL.md\n(instructions)" as SKILL
+  component "assets/\nphase-checklist.md" as CHECKLIST
+  component "evals/evals.json" as EVALS
+}
+
+package "Project Artifacts (specs/)" {
+  component "requirements.md" as R
+  component "design.md" as D
+  component "tasks.md" as T
+  component "impl-plan.md" as I
+  component "STATUS.md\n(resume point)" as STATUS
+  component "crs/CR-N-*.md\n(change requests)" as CR
+}
+
+package "Codebase" {
+  component "source code" as CODE
+  component "tests" as TESTS
+}
+
+actor Developer
+
+Developer --> SKILL : describe project / "continue"
+SKILL --> R : phase 1
+SKILL --> D : phase 2
+SKILL --> T : phase 3
+SKILL --> I : phase 4
+SKILL --> CODE : phase 5
+SKILL --> TESTS : phase 6
+SKILL --> STATUS : tracks progress
+SKILL --> CR : change requests
+CHECKLIST ..> SKILL : phase gate rules
+@enduml

skills/sdlc/assets/phase-checklist.md

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+# Phase Quick-Reference Checklist
+
+## Phase 1 — Requirements
+- [ ] Problem statement written (1–3 sentences)
+- [ ] Functional requirements listed (FR-N format)
+- [ ] Non-functional requirements listed
+- [ ] Constraints documented
+- [ ] Out-of-scope items explicit
+- [ ] Open questions listed
+
+## Phase 2 — Design
+- [ ] Architecture style chosen with rationale
+- [ ] Component diagram (PlantUML)
+- [ ] Data model diagram (PlantUML)
+- [ ] External dependencies table
+- [ ] ADRs written (decision + rationale)
+- [ ] Risks table with mitigations
+
+## Phase 3 — Tasks
+- [ ] Work grouped into milestones
+- [ ] Each task: estimable, independent, linked to FR
+- [ ] Dependencies identified
+- [ ] Critical path flagged
+- [ ] Parallelizable tasks noted
+
+## Phase 4 — Implementation Plan
+- [ ] Setup checklist written
+- [ ] Tasks ordered by dependency + priority
+- [ ] Each task has acceptance criteria
+- [ ] Each task has implementation notes
+- [ ] Each task has Definition of Done
+- [ ] "Day 1" first task identified

skills/sdlc/assets/workflow.puml

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+@startuml sdlc-workflow
+skinparam defaultFontName Arial
+skinparam backgroundColor #FAFAFA
+
+actor Developer
+participant "sdlc Skill" as SKILL
+participant "specs/" as FS
+
+Developer -> SKILL : describe project
+SKILL -> FS : write requirements.md
+SKILL --> Developer : phase 1 complete ✓
+Developer -> SKILL : "done"
+
+SKILL -> FS : write design.md
+SKILL --> Developer : phase 2 complete ✓
+Developer -> SKILL : "done"
+
+SKILL -> FS : write tasks.md
+SKILL --> Developer : phase 3 complete ✓
+Developer -> SKILL : "done"
+
+SKILL -> FS : write impl-plan.md
+SKILL --> Developer : phase 4 complete ✓
+Developer -> SKILL : "done"
+
+SKILL -> FS : write source code
+SKILL -> FS : run tests → update STATUS.md
+SKILL --> Developer : phase 5 & 6 complete ✓
+
+note over Developer, SKILL
+  At any point: "continue" resumes from STATUS.md
+  After completion: describe a CR to add features
+end note
+@enduml