Belt-and-braces: the UI now disables the Delete button when a group
is the only one on the host (with a tooltip explaining why), and the
server-side handler returns 409 if a curl/form-replay tries anyway.
Every host needs at least one source group to be backup-able, so the
'last group on a fresh host' case is a meaningful accident to guard
against.
Sources tab now lists every source group on the host with per-row
counts (used-by-N-schedules, snapshot count by tag), the v4
conflict tag (keep-* dimension that has no compatible cadence),
and Run-now / Edit / Delete actions. Run-now reuses the existing
HTMX-aware /hosts/{id}/source-groups/{gid}/run handler.
New /hosts/{id}/sources/new and /sources/{gid}/edit form: name +
includes/excludes textareas + the 3×2 keep-* retention grid +
retry-on-offline knobs. Server-side validation re-renders with the
operator's input intact; the inline conflict banner shows above the
retention grid when ConflictDimension is set.
Delete blocks (UI + server) when the group is referenced by any
schedule. Every successful mutation calls pushScheduleSetAsync so
an online agent re-arms within seconds.
Adds .src-row and .keep-cell to input.css for the row + retention
grid layout.
Extract header/vitals/sub-tabs into a host_chrome partial that every
host-detail tab page renders. Sources / Schedules / Repo go from
inert divs to real <a> links backed by stub pages that share the
chrome and a 'coming next' body — slices 2/3/4 fill them in.
Also re-establishes the version indicator (host_schedule_version vs
agent's applied_schedule_version) in the header.
Drops the legacy fat-schedule list/edit templates that referenced
fields removed by the P2 redesign (Manual / Paths / RetentionPolicy
on Schedule); the new templates land in slice 3.
steve