Route-Share Canary

Retired by the #1041 route-share reset.

The old canary drove a pre-reset two-turn route-share flow. That flow is intentionally gone: every option now gets its own public page/link preview, and users iterate by replying to the specific option message they like.

Use the reset harnesses instead:

imperfect-cli route-share-devstack up --smoke --exit-after-smoke
imperfect-cli route-share-e2e --manifest-json manifest.json --route-options-json route-options.json
imperfect-cli route-share-e2e --live --artifact-dir tmp/route-share-e2e-live

See docs/route-share-devstack.md and docs/route-share-e2e-harness.md.