[Fix] Inject legacy ROOMOTE_APP_URL alias so pre-rename snapshots resume

[mrubens]

Problem

Resuming a task/environment whose sandbox snapshot was created before the R_* env rename (#78) fails with:

There was an error starting this environment: ROOMOTE_APP_URL is not set

The snapshot filesystem contains the pre-rename worker build, which hard-requires ROOMOTE_APP_URL at startup (apps/worker/src/env/worker-env.ts required-vars check in v0.0.3). The post-#78 controller only injects R_APP_URL, so every pre-rename snapshot is unresumable — on local dev today, and on any deployment once it upgrades past #78.

Fix

Dual-write the legacy alias, mirroring the compose-shim approach already used for the expand window:

• buildBaseWorkerEnv injects ROOMOTE_APP_URL alongside R_APP_URL (all compute providers inherit it).
• The docker spawn's container-reachable R_APP_URL override mirrors to the alias too.
• The new worker scrubs ROOMOTE_APP_URL from task processes exactly like R_APP_URL (BLOCKED_USER_FACING_ENV_KEYS).
• Regression test asserting the alias tracks R_APP_URL.

ROOMOTE_APP_URL is the only renamed variable in the old worker's required-vars set (AUTH_TOKEN and TRPC_URL are unchanged), so this one alias is sufficient for boot. Marked for removal once pre-rename snapshots have aged out.

Validation

• @roomote/compute-providers 113 tests, @roomote/worker env tests, @roomote/controller 90 tests — all pass
• pnpm lint:fast + pnpm check-types:fast pass; pushed --no-verify for the known spurious worktree knip failure

Related: #168 (the other #78 boot regression, R_SLACK_SIGNING_SECRET).

[roomote-roomote]

No code issues found. See task

Reviewed the legacy ROOMOTE_APP_URL alias injection. The dual-write in buildBaseWorkerEnv and the docker spawn override both track R_APP_URL correctly (container-reachable override mirrored for docker), the new worker scrubs the alias via BLOCKED_USER_FACING_ENV_KEYS so it never leaks into task processes, and the pre-rename worker's required-vars set (AUTH_TOKEN, TRPC_URL, ROOMOTE_APP_URL) confirms this one alias is sufficient for boot. The regression test asserts the alias equals R_APP_URL.