chore: mark tty/review-tty-final as completed — all 15 tasks done

Final review verified:
- 103 tests pass (61 alknet-tty + 42 alknet-tty-local), clippy clean, fmt clean
- Cross-crate seam: portable_pty only in alknet-tty-local, not in alknet-tty default
- ADR-055 exit-chunk-is-last enforced in adapter, validated in integration tests
- ADR-056 cancel-cleanup guards in both PTY and pipe exit futures, integration tests confirm no orphans
- REQ-TTY-01 three-thread bridge, REQ-TTY-02 process-group signal forwarding
- No bollard/russh/alknet-call deps; alknet-tty depends on alknet-core only
- Deviation: local feature re-export deferred to assembly layer (cargo cycle constraint)

tasks/tty/review-tty-final.md

@@ -1,7 +1,7 @@
 ---
 id: tty/review-tty-final
 name: Final review of alknet-tty + alknet-tty-local for merge readiness
-status: pending
+status: completed
 depends_on: [tty/integration-test]
 scope: broad
 risk: low