Migrated from Method backlog

This issue was created from a legacy filesystem backlog card. GitHub Issues are now the live work tracker; repository docs remain Method evidence.

Source backlog: docs/method/backlog/asap/PLATFORM_ttd-rollback-playbooks.md
Original lane: asap
Original legend: PLATFORM

Original backlog card

Commit-ordered rollback playbooks for TTD integration

Ref: #282

Status: active and not yet implemented. Echo has live TTD-facing surfaces, but
no owned rollback playbook for protocol or adapter breakage.

Document rollback procedures for the TTD integration path. If a warp-ttd
protocol change or Echo adapter change breaks the integration, the repo needs a
commit-ordered rollback sequence instead of improvised reverts.

Current integration seams:

• crates/ttd-protocol-rs and packages/ttd-protocol-ts are generated
  protocol consumers.
• crates/echo-ttd owns Echo-side compliance and violation reporting.
• crates/echo-wasm-bindings/src/ttd.rs is a local legacy TTD binding surface.
  The former crates/ttd-browser debugger/browser prototype has been removed
  from Echo's active workspace.
• warp-ttd owns debugger protocol semantics; Echo owns generated consumer
  wiring and substrate-side compatibility.

Work:

• Write the rollback sequence for protocol schema changes:
  • revert generated Rust/TS protocol artifacts
  • revert adapter glue that depends on the schema
  • restore compliance expectations or mark them explicitly incompatible
  • rerun the narrow TTD/compliance verification commands
• Write the rollback sequence for Echo adapter changes that break a stable
  warp-ttd protocol.
• State which repo owns each revert decision and which commits must move first.
• Coordinate with PLATFORM_ttd-schema-reconciliation so schema provenance and
  rollback provenance do not drift separately.

Done looks like:

• One playbook doc names the rollback owner split between Echo and warp-ttd.
• The playbook includes before/after validation commands.
• The sequence distinguishes protocol rollback from Echo adapter rollback.
• Generated artifacts remain treated as consumers, not protocol authority.