## Summary
- Add `Embed` and `HasEmbed` structs to `directive.h` for storing
`#embed` / `__has_embed` directive info
- Implement `EmbedDirective` and `HasEmbed` PPCallbacks in
`DirectiveCollector`, using the current `CompilationUnitRef` API
- Add unit tests for both directives (including non-existent file
handling)
Rebased onto current main, resolving conflicts from the `Compiler/` →
`compile/` restructuring and the `CompilationUnitRef` API migration.
Original PR by @Guo-Shiyu.
## Test plan
- [x] `pixi run unit-test` — 465 tests passed, 0 failures
Co-authored-by: ykiko <ykikoykikoykiko@gmail.com>
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>