…ype, checkpointer

Add missing `import uvicorn` and `from langgraph.checkpoint.memory import
MemorySaver`, fix port from string to int, add checkpointer to
graph.compile() to prevent ValueError.

Supersedes #3661 (which had a typo: langgrapg → langgraph).

- gpt-5.2/gpt-5.2-mini → gpt-5.4/gpt-5.4-mini across 70 files
- Anthropic model IDs: dots → hyphens (claude-sonnet-4-5, not 4.5)
- LangGraph FastAPI: add missing uvicorn import, MemorySaver checkpointer,
  fix port string→int
- AG2: ContextVariables import moved to autogen.agentchat
- CrewAI Flows: comment out deprecated CLI option
- Pydantic: pin Starlette 0.45.3 (1.0.0 is incompatible)
- CopilotChat: add missing default export
- All quickstarts: add globals.css import to layout examples
- LangGraph quickstart tagged with doctest="server" for Phase 1

Supersedes #3655, #3656, #3658, #3660, #3661, #3665, #3667, #3669.

## Summary

Comprehensive docs quality infrastructure — model name validation,
executable doc tests, and 8 community docs fixes rolled up.

### Docs fixes (supersedes 8 PRs)
- **gpt-5.2 → gpt-5.4** across 70 files, 124 occurrences (supersedes
#3655)
- **Anthropic model IDs** dots → hyphens to match API/AI SDK format
(supersedes #3656)
- **LangGraph FastAPI quickstart** — missing `import uvicorn`, missing
`MemorySaver` checkpointer, `port` string→int (supersedes #3661, with
contributor's `langgrapg` typo fixed)
- **AG2 ContextVariables import** — moved from `autogen` to
`autogen.agentchat` per latest AG2 (supersedes #3658, verified via
Docker)
- **CrewAI Flows** — comment out deprecated CLI option (supersedes
#3667)
- **Pydantic quickstart** — pin Starlette 0.45.3 (1.0.0 is incompatible,
verified via Docker) (supersedes #3660)
- **CopilotChat example** — add missing `default` export for Next.js
page components (supersedes #3669)
- **globals.css import** — add to all 9 quickstart layout examples so
customization section works (supersedes #3665)

### Model name validation (new)
- `docs/model-allowlist.json` — maintained list of valid model names by
provider (OpenAI, Anthropic, Google, Cohere, Meta)
- `scripts/validate-doc-model-names.ts` — CI lint that extracts model
names from docs code blocks and validates against allowlist
- 20 tests

### Executable doc tests (new, Phase 1)
- `scripts/doc-tests/extract.ts` — remark + remark-mdx AST parser finds
`doctest`-tagged code blocks in MDX
- `scripts/doc-tests/run.ts` — execution harness: installs deps, points
at aimock, runs server/script/component snippets
- `.github/workflows/test_doc-examples.yml` — CI triggered on `docs/**`
changes (previously excluded from ALL CI)
- LangGraph FastAPI quickstart tagged as first `doctest="server"`
example
- 10 tests for extraction

### Spec
[Executable Doc Tests proposal on
Notion](https://www.notion.so/33c3aa38185281388a21e8dfe752ac5e)

## Supersedes
| PR | Fix | Status |
|----|-----|--------|
| #3655 | gpt-5.2-mini → gpt-5.4-mini | ✅ Included (all 70 files, not
just 22) |
| #3656 | Anthropic dots → hyphens | ✅ Included |
| #3658 | AG2 ContextVariables import | ✅ Included (verified via Docker)
|
| #3660 | Starlette pin | ✅ Included (verified via Docker) |
| #3661 | LangGraph FastAPI quickstart | ✅ Included (with typo fix) |
| #3665 | globals.css import | ✅ Included |
| #3667 | CrewAI deprecated CLI | ✅ Included |
| #3669 | CopilotChat default export | ✅ Included |

All 8 PRs can be closed when this merges.

## Test plan
- [x] Model name validator passes (0 violations)
- [x] 20 validator unit tests pass
- [x] 10 extraction unit tests pass
- [x] Build passes
- [x] Commitlint passes
- [ ] CI workflow validates doc examples on docs/** changes

🤖 Generated with [Claude Code](https://claude.com/claude-code)