Add skill index to AGENTS.md and reorganize skills

Summary

Add a skill index section to AGENTS.md and reorganize existing skills to live next to their related code.

Context

Skills are just markdown files - no special loading mechanism. The agent reads AGENTS.md, sees what skills are available, and reads them on demand via read_file.

Skill Index to Add

Add this section to AGENTS.md:

## Skills

You can load specialized skills by reading them. Each skill contains detailed instructions for specific tasks.

### Development

| Skill | Path | When to use |
|-------|------|-------------|
| Coder | `Omni/Ide/Coder.md` | Implementing code changes |
| Reviewer | `Omni/Ide/Reviewer.md` | Reviewing diffs/PRs |
| Git | `Omni/Ide/Git.md` | Commits, branches, git-branchless |
| Build | `Omni/Bild/Skill.md` | Building, dependencies, fixing build errors |
| Debug | `Omni/Ide/Debug.md` | Tracing errors, reading logs |
| Test | `Omni/Ide/Test.md` | Writing and running tests |
| Deploy | `Omni/Deploy/Skill.md` | Deploying services |
| Feature | `Omni/Ide/Feature.md` | End-to-end feature development |

### Research

| Skill | Path | When to use |
|-------|------|-------------|
| Research | `Omni/Agent/Research.md` | Deep research, multiple sources |
| Web Research | `Omni/Agent/WebResearch.md` | Quick web lookups |
| Data Extraction | `Omni/Agent/DataExtraction.md` | Structured data from pages/docs |

### Agent

| Skill | Path | When to use |
|-------|------|-------------|
| Skill Creator | `Omni/Agent/SkillCreator.md` | Creating new skills |
| Trace Analysis | `Omni/Agent/TraceAnalysis.md` | Debugging agent runs |

### Products

| Skill | Path | When to use |
|-------|------|-------------|
| PIL Growth | `Biz/PodcastItLater/Growth.md` | Daily PIL marketing ops |
| PIL Analytics | `Biz/PodcastItLater/Analytics.md` | PIL traffic analysis |

To use a skill, read it with `read_file` and follow its instructions.

Skills to Move

| Current Location | New Location | |------------------|--------------| | Omni/Agent/Skills/shared/code-review/SKILL.md | Omni/Ide/Review.md (merge with new Reviewer skill) | | Omni/Agent/Skills/shared/feature-development/SKILL.md | Omni/Ide/Feature.md | | Omni/Agent/Skills/shared/research/SKILL.md | Omni/Agent/Research.md | | Omni/Agent/Skills/shared/web-research/SKILL.md | Omni/Agent/WebResearch.md | | Omni/Agent/Skills/shared/data-extraction/SKILL.md | Omni/Agent/DataExtraction.md | | Omni/Agent/Skills/shared/skill-creator/SKILL.md | Omni/Agent/SkillCreator.md | | Omni/Agent/Skills/ben/goatcounter/SKILL.md | Biz/PodcastItLater/Analytics.md | | Omni/Agent/Skills/ben/trace-analysis/SKILL.md | Omni/Agent/TraceAnalysis.md |

Skills to Delete

| Skill | Reason | |-------|--------| | Omni/Agent/Skills/shared/deploy-qa/SKILL.md | Replaced by Omni/Deploy/Skill.md (t-327) | | Omni/Agent/Skills/ben/omni-shell/SKILL.md | Wrong abstraction - just documentation | | Omni/Agent/Skills/ben/prospect-finder/SKILL.md | Absorbed into Biz/PodcastItLater/Growth.md |

Directory to Delete

After moving all skills, delete:

• Omni/Agent/Skills/ (entire directory)

Deliverables

• [ ] Add skill index section to AGENTS.md
• [ ] Move each skill to new location
• [ ] Update skill content to remove SKILL.md naming convention (just use descriptive names)
• [ ] Delete obsolete skills
• [ ] Delete Omni/Agent/Skills/ directory
• [ ] Verify no broken references