fix: include Cython source files in source distribution

[btucker]

The build was failing because the .pyx and .pxd files were not included in the source distribution, causing this error:
ValueError: 'applefoundationmodels/_foundationmodels.pyx' doesn't match any files

Changes:

• Add applefoundationmodels/*.pyx to MANIFEST.in
• Add applefoundationmodels/*.pxd to MANIFEST.in
• Add applefoundationmodels/swift/*.h to MANIFEST.in

Summary by CodeRabbit

• Chores
  • Updated distribution packaging to include all necessary source and header files required for proper compilation.

[coderabbitai]

Caution

Review failed

The pull request is closed.

Walkthrough

The MANIFEST.in file was updated to include Cython source files (*.pyx, *.pxd) from the applefoundationmodels directory and Swift header files (*.h) from applefoundationmodels/swift in the source distribution package. These are build-time sources required for compilation.

Changes

Cohort / File(s)	Summary
Build manifest configuration MANIFEST.in	Added include directives for Cython sources (applefoundationmodels/*.pyx, applefoundationmodels/*.pxd) and Swift headers (applefoundationmodels/swift/*.h); retained existing README, LICENSE, and Swift file inclusions.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~3 minutes

• Single, straightforward manifest configuration file with additive include directives
• No logic changes or behavioral implications

Possibly related PRs

• fix: include libfoundation_models.dylib in wheels and build for multiple python versions #3 — Also modifies MANIFEST.in to control which source artifacts and native binaries are included in distributions.

Poem

🐰 A manifest grows with sources so fine,
Cython and Swift headers, all in line—
The build box opens, no secrets to hide,
Compilation flows with ease and with pride! ✨

✨ Finishing touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch feature/source-dist

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📜 Recent review details

Configuration used: CodeRabbit UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 29e58e3 and b858121.

📒 Files selected for processing (1)

• MANIFEST.in (1 hunks)

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