P2 redesign · phase 2: store rewrite — sources, slim schedules, repo maintenance

Go-side data model rebuilt against migration 0008. The fat-Schedule
shape (paths/excludes/tags/retention/manual/kind/options/hooks) is
gone; that surface lives on source_groups now.

* store/types.go
  - Schedule slimmed to {id, host_id, cron, enabled, source_group_ids,
    timestamps}. SourceGroupIDs populated by Get/List, accepted on
    Create/Update so callers pass desired junction state in one shape.
  - SourceGroup added: name (= snapshot tag), includes/excludes,
    retention_policy, retry_max + retry_backoff_seconds, cached
    conflict_dimension.
  - HostRepoMaintenance added: forget/prune/check cadences + enabled.
  - PendingRun added: offline-retry queue.
  - Host loses RepoInitialisedAt; gains BandwidthUpKBps + BandwidthDownKBps.
  - RetentionPolicy moves home from "schedule field" to "source group
    field" but the type itself + Summary() method unchanged.

* store/sources.go (new) — CRUD + GetByName + ConflictDimension cache.
  Group writes bump host_schedule_version; conflict cache writes don't
  (server-internal projection, agent doesn't see it).
* store/maintenance.go (new) — CreateDefault is idempotent (INSERT OR
  IGNORE). UpdateRepoMaintenance doesn't bump schedule version because
  these run on the server's own ticker, not the agent's local cron.
* store/pending.go (new) — Enqueue / DueRunsForRetry / Bump / Delete.
* store/schedules.go — rewritten for slim shape + junction CRUD.
  Update wipes the schedule_source_groups junction wholesale and
  re-inserts (simpler than diffing). Adds SchedulesUsingGroup for
  retention-conflict detection + UI labels.
* store/hosts.go — drops repo_initialised_at scan, adds bandwidth scan.
  New SetHostBandwidth helper.

* HTTP layer — temporarily stubbed during this rewrite (501 returns
  with redesign_in_progress error code). Phase 3 fills these in
  against the new shape:
    - schedules.go REST CRUD
    - schedule_push.go agent reconciliation
    - ui_schedules.go HTML form CRUD
  Run-now-per-host + Init-repo handlers in ui_handlers.go also stubbed
  — both go away in the new model (Run-now per source group; auto-init
  at host enrolment).

* enrollment.go — replaces "seed manual schedule from typed paths"
  with "seed default source group + repo-maintenance row." The default
  group gets the typed paths as its includes; operator edits later
  via Sources tab.

* ws/handler.go — drops the MarkHostRepoInitialised projection (column
  is gone; auto-init makes it derivable from latest init job's status).

Tests:
* store: existing schedule test rewritten for slim shape + junction;
  new sources_test.go covers source-group CRUD, name uniqueness,
  conflict cache, repo-maintenance defaults + idempotent seed,
  pending-runs queue lifecycle.
* http: schedules_test.go and schedule_push_test.go deleted — both
  exercised the obsolete fat-schedule API. Phase 3 rewrites them
  against the new endpoints.

go test ./... green. cmd/server + cmd/agent build. The UI is broken
end-to-end (schedules / sources / repo tabs all hit 501 stubs); Phase 3
restores REST + on-the-wire reconciliation; Phase 4 rewires the UI
templates against the new model.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

internal/server/http/enrollment.go

@@ -140,26 +140,24 @@ func (s *Server) handleAgentEnroll(w stdhttp.ResponseWriter, r *stdhttp.Request)
 		return
 	}
 
-	// Seed an initial manual schedule from whatever paths the
-	// operator typed into Add-host. The schedule is editable from
-	// the host's Schedules tab; the operator can add automated
-	// schedules alongside it later. We skip this when no paths
-	// were supplied — the host can still enrol; it just can't
-	// back up until the operator adds a schedule.
-	if len(attachments.InitialPaths) > 0 {
-		seed := store.Schedule{
-			ID:       ulid.Make().String(),
-			HostID:   hostID,
-			Kind:     string(api.JobBackup),
-			CronExpr: "",
-			Paths:    attachments.InitialPaths,
-			Enabled:  true,
-			Manual:   true,
-		}
-		if err := s.deps.Store.CreateSchedule(r.Context(), &seed); err != nil {
-			slog.Warn("enrollment: seed manual schedule failed",
-				"host_id", hostID, "err", err)
-		}
+	// Seed the host's "default" source group with whatever paths the
+	// operator typed into Add-host (empty allowed; group is editable
+	// from the Sources tab post-enrol). Also seed the host's
+	// repo-maintenance row with default cadences so forget/prune/check
+	// start ticking on their own. Auto-init dispatch lands in Phase 6
+	// of the redesign.
+	if err := s.deps.Store.CreateSourceGroup(r.Context(), &store.SourceGroup{
+		ID:       ulid.Make().String(),
+		HostID:   hostID,
+		Name:     "default",
+		Includes: attachments.InitialPaths,
+	}); err != nil {
+		slog.Warn("enrollment: seed default source group failed",
+			"host_id", hostID, "err", err)
+	}
+	if err := s.deps.Store.CreateDefaultRepoMaintenance(r.Context(), hostID); err != nil {
+		slog.Warn("enrollment: seed repo maintenance failed",
+			"host_id", hostID, "err", err)
 	}
 
 	// Promote the encrypted repo creds onto the freshly-created host