Tasks: Approval reconciliation

Setup

• T001 Record requirements and plan in specs/022-approval-reconcile/spec.md and plan.md.

User story 1

• T002 [US1] Extend the existing native approval regression in crates/signaltty-gui/src/terminal.rs and prove it fails.
• T003 [US1] Reuse the Decision snapshot to detect current choice changes in crates/signaltty-gui/src/terminal.rs.
• T004 [US1] Verify read-only toggles, option callbacks, stable buttons and VTE identity in crates/signaltty-gui/src/terminal.rs.

Verification

• T005 Inspect native light/dark renders and run scripts/verify.sh full; record docs/qa/ evidence.
• T006 Update docs/06-gui-toolkit.md and complete independent diff review.