refactor: extract bundled Sapling provider

[benvinegar]

Summary

• move the bundled Sapling provider into private workspace packages/hunk-sapling (@hunk/sapling)
• remove obsolete Hunk compatibility re-exports after migrating remaining callers
• harden boundaries across all private VCS workspaces and published package checks
• preserve provider order (jj, sl, git), Git fallback, and --no-extensions behavior

Validation

• full unit suite: 2,084 tests
• 150 PTY integration tests
• typecheck, lint, Knip, dependency boundaries
• npm and prebuilt package checks plus install smoke

This is PR 4 of 4 and completes Phase 2. Sapling executable-backed tests were unavailable locally; mocked and package-isolation coverage passed.

This PR description was generated by Pi using GPT-5.6 Sol

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1 Skipped Deployment

Project	Deployment	Actions	Updated
hunk-web	Ignored	Preview	Sep 6, 2026 5:12am UTC

[greptile-apps]

Greptile Summary

This PR extracts the bundled Sapling implementation into a private @hunk/sapling workspace and aligns all bundled VCS providers around the public extension contract and shared @hunk/vcs leaves.

• Adds Sapling workspace, lockfile, Nix, TypeScript, Knip, and dependency-boundary wiring.
• Updates bundled provider composition while preserving activation order.
• Removes host-side compatibility re-export modules and imports shared VCS helpers directly.
• Strengthens package and architecture checks, but the new isolated provider smoke-test setup cannot resolve the unbuilt hunkdiff/extension export.

Confidence Score: 4/5

The PR is not safe to merge until the isolated provider package tests resolve the public extension entry from a built or source-compatible fixture.

All three provider package smoke tests fail in a clean checkout because the copied hunkdiff package exports hunkdiff/extension from absent generated output, making the repository’s default test suite fail.

Files Needing Attention: scripts/hunk-sapling-package.test.ts, scripts/hunk-git-package.test.ts, scripts/hunk-jj-package.test.ts

Important Files Changed

Filename	Overview
packages/hunk-sapling/src/index.ts	Moves the Sapling adapter into its private workspace while retaining the public extension contract and provider behavior.
packages/hunk/src/extensions/default/vcs/index.ts	Replaces the relative Sapling import with @hunk/sapling without changing bundled registration order.
scripts/hunk-sapling-package.test.ts	Adds package-boundary coverage, but its isolated consumer copies an unbuilt hunkdiff package whose extension export cannot resolve.
scripts/hunk-git-package.test.ts	Adds hunkdiff to the isolated provider fixture using the same unbuilt-package setup that fails module resolution.
scripts/hunk-jj-package.test.ts	Adds hunkdiff to the isolated provider fixture using the same unbuilt-package setup that fails module resolution.
scripts/check-pack.ts	Tightens published-file validation and checks that private provider imports do not survive in the runtime bundle.
scripts/source-boundaries.test.ts	Extends provider-boundary enforcement to Sapling and narrows composition-root package exceptions.

Prompt To Fix All With AI

### Issue 1
scripts/hunk-sapling-package.test.ts:70-72
**Provider smoke tests cannot load**

This copies the source `hunkdiff` workspace into the temporary consumer, but `hunkdiff/extension` resolves only to generated files under `dist/npm/extension`, which the test does not build. Importing the provider therefore fails with `Cannot find module 'hunkdiff/extension'`. Since the default suite includes `scripts/`, this breaks the test suite in a clean checkout. The Git and Jujutsu package tests use the same broken setup.

---

For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.

_{Reviews (1): Last reviewed commit: "refactor: extract bundled Sapling provid..." | Re-trigger Greptile}

[greptile-apps]

Provider smoke tests cannot load

This copies the source hunkdiff workspace into the temporary consumer, but hunkdiff/extension resolves only to generated files under dist/npm/extension, which the test does not build. Importing the provider therefore fails with Cannot find module 'hunkdiff/extension'. Since the default suite includes scripts/, this breaks the test suite in a clean checkout. The Git and Jujutsu package tests use the same broken setup.

Knowledge Base Used: Distribution and release tooling

Prompt To Fix With AI

This is a comment left during a code review.
Path: scripts/hunk-sapling-package.test.ts
Line: 70-72

Comment:
**Provider smoke tests cannot load**

This copies the source `hunkdiff` workspace into the temporary consumer, but `hunkdiff/extension` resolves only to generated files under `dist/npm/extension`, which the test does not build. Importing the provider therefore fails with `Cannot find module 'hunkdiff/extension'`. Since the default suite includes `scripts/`, this breaks the test suite in a clean checkout. The Git and Jujutsu package tests use the same broken setup.

**Knowledge Base Used:** [Distribution and release tooling](https://app.greptile.com/modem/-/custom-context/knowledge-base/modem-dev/hunk/-/docs/distribution-and-release-tooling.md)

---

For each issue above, determine whether it is valid and should be fixed. If so, fix it directly.