build: bump tools/rust_api to package the single-file header script

[kory-io]

Problem

lbug 0.21.1 on crates.io still can't be built from source (LBUG_BUILD_FROM_SOURCE=1):

make[2]: *** No rule to make target `.../lbug-0.21.1/lbug-src/scripts/collect-single-file-header.py', needed by `src/lbug.hpp'.  Stop.

The fix was merged in LadybugDB/ladybug-rust#43 (28aba1c4). The crate is packaged from this repo's tools/rust_api submodule, though, which is still pinned at ca706e51, one commit before the fix. So 0.21.0, 0.21.0-pre.20260929 and 0.21.1 all ship the old include list: build.rs turns BUILD_SINGLE_FILE_HEADER on, but lbug-src/scripts/collect-single-file-header.py and headers.txt aren't in the package.

Fix

Bump tools/rust_api from ca706e51 to 28aba1c4. That commit's only change is the packaging fix: the two script files are added to package.include, with matching rerun-if-changed lines.

Verification

• Before: the published 0.21.1 crate has neither file, and a from-source build fails as shown above.
• After: packaging 28aba1c4 with LBUG_BUILD_FROM_SOURCE=1 cargo package succeeds. Cargo's verification step builds the tarball from source and generates lbug.hpp (shown in build: package the single-file header script for source builds ladybug-rust#43).

A 0.21.2 from this commit would let crates that build from source use 0.21.

[kory-io]

@adsharma Thanks for merging this! Since 0.21.1 was cut just before it, the published crate still can't build from source. Would it be possible to cut a 0.21.2 when you get a chance? Happy to help test it.

[adsharma]

@kory-io if you're building from source why not build from ladybug-rust git repo?

[kory-io]

Thanks @adsharma! We did try that. A git dependency on ladybug-rust alone doesn't include the C++ sources (lbug-src is only added at publish time), and pointing at the ladybug repo instead doesn't find them either on macOS/Linux, because the in-repo ../.. fallback in get_lbug_root() is Windows-only. So either way it needs LBUG_SOURCE_DIR.

For now we're building against a v0.21.1 checkout with LBUG_SOURCE_DIR, and that works fine. A 0.21.2 would still be nice, since it lets our CI build from the crate alone. I'm also happy to send a small PR enabling that ../.. fallback on all platforms, so git dependencies build out of the box, if that's useful.