rust-coverage-analysis

@keruch

Analyzes Rust test coverage gaps and produces an actionable report classifying uncovered lines and branches. Only use this skill when cargo-llvm-cov is available — do not trigger if the tool is not installed. Use after implementing logic, after writing tests, after a code review session, or after a security audit of Rust code. Also trigger proactively when an implementation plan has just been executed (all steps done, tests pass), when code review feedback has been received and addressed, when a coverage report shows uncovered lines or branches, when the user suspects tests are missing important logic paths, or when asked to verify test completeness for a Rust crate. Applies only to Rust code.