fix: Match JIT inputs for affected tasks (#13426)
## Summary
- match startup and JIT task inputs independently before combining their
results
- preserve exclusions and package boundaries for tasks with JIT inputs
- restrict JIT traversal inputs to explicitly declared files
- add regressions for excluded Markdown files and unrelated packages
## Testing
- `cargo fmt --all -- --check`
- `cargo test -p turborepo-types task_input_matching`
- `cargo test -p turborepo-engine affected`
- `cargo clippy -p turborepo-types --all-targets -- -D warnings`
- pre-push formatting and TOML checks
Closes #13422
