Include link_deps in Rust runfiles

[finn-ball]

Summary

• merge default runfiles from link_deps into Rust target runfiles
• include dynamic libraries supplied through link_deps alongside those from deps

Why

link_deps participates in native linking, but its runfiles and dynamic libraries were omitted when rustc_compile_action assembled runtime files. Binaries and library targets that link native dependencies through link_deps could therefore be built successfully while missing required runtime artifacts.

Impact

Rust binaries, cdylibs, and staticlibs now carry the runtime files needed by dependencies declared through link_deps.

Validation

• bazel test //test/unit/link_deps:all
• git diff --check

[krasimirgg]

Thank you! Looks good!