Command contract: finish the FEAT-02x adoption or fold crates/command-contract

From the 0.9.14 refactor backlog.

`crates/command-contract` is explicitly shapes-only (FEAT-014) while `tui/src/commands/contract.rs` (~6.5k) plus `commands/` (~61k) hold the live dispatch. FEAT-020/021/023/024 adopted shapes group by group in 0.9.13; the remaining work is the last groups plus deleting the tui-side copy. Decide honestly whether the crate earns its keep: if the tui contract file is already the shape everything uses, the crate may be the abandoned side.

Size: M. Acceptance: one contract location, the migration manifest gate (`scripts/check-command-migration-manifest.py`) reflects it.

Read crates/command-contract, tui/src/commands/contract.rs, and the tui commands/ directory to compare the shapes-only crate with the live dispatch. Run scripts/check-command-migration-manifest.py before and after reviewing the remaining FEAT-020/021/023/024 groups. Done means choosing one contract location, completing the remaining adoption or folding the crate, and updating the migration manifest gate.

Written by the indexing model from the issue text.