P3-09 — snapshot diff dispatcher.
- POST /api/hosts/{id}/snapshots/diff (and the unprefixed HTMX-form
variant) takes {snapshot_a, snapshot_b}, validates both belong to
the host (long id / short id / prefix match), checks the agent is
online, mints a JobDiff, ships command.run with DiffPayload, writes
a host.snapshot_diff audit row, returns HX-Redirect to the live
job page (or JSON {job_id, job_url} for REST callers).
- Two-snapshot guard: POSTing diff(a,a) returns 422.
- UI: small panel on the host_detail right rail (visible when the
host has 2+ snapshots) with two short-id inputs and a Diff button.
Output renders on the standard live job page where the operator
reads the per-line diff text directly.
P3-X3 — recent-restores line.
- hostChromeData grows RestoreStatus / RestoreAt / RestoreJobID
populated via store.LatestJobByKind(host_id, 'restore') (already
exists, used by the init line).
- host_chrome.html renders a small line below the existing init-status
one with status-coloured copy + a link to the job log. Hidden when
no restore has ever run on this host.
Tests:
- diff_test covers happy path (correct DiffPayload + HX-Redirect),
same-id rejection (422), unknown-id rejection (422). Adds a
seedTwoSnapshots helper since ReplaceHostSnapshots is atomic-swap
(calling seedSnapshot twice would only leave the second).
Restage block (CLAUDE.md) deferred to the end of the restore phase.
