meta: label good first issues to onboard open source contributors

## Goal
`good first issue` labels are the primary way open source contributors find their first contribution. Each issue should be scoped, specific, and self-contained.

## Candidate good first issues to create
- [ ] Build `viz-code-editor` primitive (Monaco/CodeMirror pane following the viz-* pattern)
- [ ] Build `viz-connection` primitive (API key picker that reads `.env.nextviz` key names)
- [ ] Migrate `log-data.tsx` to three-file folder structure (see Issue #3)
- [ ] Migrate `on-http.tsx` to three-file folder structure (see Issue #3)
- [ ] Write `docs/nodes/ai-agent.md` following the node doc format in `docs/nodes/README.md`
- [ ] Write `docs/nodes/schedule-trigger.md`
- [ ] Write `docs/nodes/chat-trigger.md`
- [ ] Add Filter / If-Else node (pure logic, no dependencies)

## Notes
- Each issue should link to the relevant docs (CONTRIBUTING.md, three-file pattern, viz-* guide)
- Scope them so a contributor can finish in one sitting
- Doc issues are especially good for first-timers who aren't ready to write node logic yet