fix: Remove incremental task caching (#13773)
## Summary
- Remove the incremental task cache implementation and executor
integration.
- Remove its configuration model, future flag, telemetry, run summaries,
generated binding, dependencies, tests, and documentation.
- Preserve unrelated Cargo incremental compilation and sccache summary
behavior.
## Testing
- `cargo fmt --all`
- `cargo test -p turborepo-run-cache`
- `cargo test -p turborepo-turbo-json`
- `cargo test -p turborepo-engine -p turborepo-run-summary -p
turborepo-task-executor -p turborepo-lib`
- Pre-push formatting and TOML checks
`cargo lint` remains blocked by the existing
`clippy::too_many_arguments` failure in
`crates/turborepo-filewatch/src/lib.rs:1633`.
