v0.28.3

release: Sem 0.28.3 (#537)

Release the merged ignore-handling fix (#536), caller-batch lookup reuse
(#534), and publishing reliability improvements. Synchronizes all five
workspace crate versions, internal dependencies, Cargo.lock, npm, MCP
metadata, and changelog. Validation: locked offline Cargo metadata and
git diff --check passed; the underlying fix passed focused regressions
and all CI checks, including Windows.