[jayleaton]

Stacked on #121 (← #111 ← #109). Builds on #99 (JJ's fix of the docs sentence). #99 edits README.md, but since #107 that paragraph lives in docs/backups.md. This PR rewrites it there, because setup now sets the schedule itself. Once #99 lands I rebase over it.

Summary

Railway's own Postgres volume snapshots (Pro plan) could only be turned on in the dashboard. Now they are declared next to the rest of the project and applied idempotently. Source: jayleaton/auto-visuals#46 (snapshot part only; the template already has the nightly encrypted backups).

 deploy/platform.yaml
 backups:
+  # volume_snapshots: [daily, weekly, monthly]   # absent: dashboard's; []: none
 per_environment:
+  staging: { volume_snapshots: [daily] }         # optional override
 cmd/railway-setup/snapshots.go   (per environment, after the IaC apply)
+  for each Postgres volume:
+    have := volumeInstanceBackupScheduleList(volume)
+    if have != want: volumeInstanceBackupScheduleUpdate(volume, kinds: want)   # no redeploy
+    refused (Hobby): warning + next step, apply continues
 docs/railway-go-iac-issues.md    + #19: volume backup schedules cannot be declared

Evidence

Throwaway project gfs-deploy-261023, backups.volume_snapshots: [daily, weekly, monthly] with per_environment.staging.volume_snapshots: [daily]:

• Before (API, both volumes): volumeInstanceBackupScheduleList → [].
• Plan: + staging/postgres Railway volume snapshots none -> daily, + production/postgres Railway volume snapshots none -> daily,monthly,weekly, exit 2. In the same run, railway config plan says already up to date in both environments: IaC cannot see the schedule.
• Apply: ✓ staging/postgres … none -> daily, ✓ production/postgres … none -> daily,monthly,weekly, exit 0, no deployments.
• Plan again: Up to date., exit 0 (idempotent).
• After (API): production ["DAILY 6d","WEEKLY 27d","MONTHLY 89d"], staging ["DAILY 6d"] (retentionSeconds / 86400).
• Validation: volume_snapshots: [daily, hourly] → backups.volume_snapshots: "hourly" must be one of [daily weekly monthly].
• make deploy-vars ok; make check-fast ok in 4.1s.

Not exercised: the Hobby refusal path. The proof workspace accepts the mutation, so the next-step branch is untested.

Merge Danger

Door: two-way. Removing the key stops managing the schedule, and [] stops new snapshots. Existing snapshots are never deleted by setup.

Blast Radius: deploys

Only projects that add volume_snapshots are affected. It stays commented out in the template, so Hobby projects see no change.

🤖 Generated with Claude Code