P2R-02 slice 1: host-detail sub-tab skeleton

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.

internal/server/http/ui_schedules.go

@@ -1,38 +1,83 @@
 package http
 
 import (
+	"errors"
+	"log/slog"
 	stdhttp "net/http"
+
+	"github.com/go-chi/chi/v5"
+
+	"gitea.dcglab.co.uk/steve/restic-manager/internal/store"
 )
 
-// ui_schedules.go — HTML form-driven schedule CRUD.
-//
-// Stubbed during the P2 redesign template rewrite. Phase 4 of the
-// redesign rebuilds the schedule editor against the new slim shape
-// (cron + source-group multi-select + enabled), the source-group
-// list/edit pages, and the repo-maintenance tab. Until then these
-// routes return 501; the dashboard's host-row "View →" link is the
-// only operator entry point that still works.
+// ui_schedules.go — HTML form-driven schedule CRUD against the slim
+// shape (cron + source-group multi-select + enabled). The list view
+// is live as of slice 1 of P2R-02; the new/edit/delete/run handlers
+// land in slice 3.
+
+// hostSchedulesPage is the data the schedules-tab template renders.
+type hostSchedulesPage struct {
+	hostChromeData
+}
 
 func (s *Server) handleUISchedulesList(w stdhttp.ResponseWriter, r *stdhttp.Request) {
-	stdhttp.Error(w, "schedules UI is being rebuilt — see P2 redesign Phase 4", stdhttp.StatusNotImplemented)
+	u := s.requireUIUser(w, r)
+	if u == nil {
+		return
+	}
+	host, ok := s.loadHostForUI(w, r)
+	if !ok {
+		return
+	}
+	view := s.baseView(u, "dashboard")
+	view.Title = host.Name + " schedules · restic-manager"
+	view.Page = hostSchedulesPage{
+		hostChromeData: s.loadHostChrome(r, *host, "schedules", "schedules"),
+	}
+	if err := s.deps.UI.Render(w, "host_schedules", view); err != nil {
+		slog.Error("ui: render host_schedules", "err", err)
+		stdhttp.Error(w, "internal", stdhttp.StatusInternalServerError)
+	}
 }
 
 func (s *Server) handleUIScheduleNewGet(w stdhttp.ResponseWriter, r *stdhttp.Request) {
-	stdhttp.Error(w, "schedules UI is being rebuilt — see P2 redesign Phase 4", stdhttp.StatusNotImplemented)
+	stdhttp.Error(w, "schedule editor lands in P2R-02 slice 3", stdhttp.StatusNotImplemented)
 }
 
 func (s *Server) handleUIScheduleEditGet(w stdhttp.ResponseWriter, r *stdhttp.Request) {
-	stdhttp.Error(w, "schedules UI is being rebuilt — see P2 redesign Phase 4", stdhttp.StatusNotImplemented)
+	stdhttp.Error(w, "schedule editor lands in P2R-02 slice 3", stdhttp.StatusNotImplemented)
 }
 
 func (s *Server) handleUIScheduleSave(w stdhttp.ResponseWriter, r *stdhttp.Request) {
-	stdhttp.Error(w, "schedules UI is being rebuilt — see P2 redesign Phase 4", stdhttp.StatusNotImplemented)
+	stdhttp.Error(w, "schedule editor lands in P2R-02 slice 3", stdhttp.StatusNotImplemented)
 }
 
 func (s *Server) handleUIScheduleDelete(w stdhttp.ResponseWriter, r *stdhttp.Request) {
-	stdhttp.Error(w, "schedules UI is being rebuilt — see P2 redesign Phase 4", stdhttp.StatusNotImplemented)
+	stdhttp.Error(w, "schedule editor lands in P2R-02 slice 3", stdhttp.StatusNotImplemented)
 }
 
 func (s *Server) handleUIScheduleRun(w stdhttp.ResponseWriter, r *stdhttp.Request) {
-	stdhttp.Error(w, "schedules UI is being rebuilt — see P2 redesign Phase 4", stdhttp.StatusNotImplemented)
+	stdhttp.Error(w, "schedule editor lands in P2R-02 slice 3", stdhttp.StatusNotImplemented)
+}
+
+// loadHostForUI is a small helper shared across the host-detail tab
+// handlers — fetches the host by URL param, writing the appropriate
+// 404/500 + returning ok=false on failure.
+func (s *Server) loadHostForUI(w stdhttp.ResponseWriter, r *stdhttp.Request) (*store.Host, bool) {
+	hostID := chi.URLParam(r, "id")
+	if hostID == "" {
+		stdhttp.NotFound(w, r)
+		return nil, false
+	}
+	host, err := s.deps.Store.GetHost(r.Context(), hostID)
+	if err != nil {
+		if errors.Is(err, store.ErrNotFound) {
+			stdhttp.NotFound(w, r)
+			return nil, false
+		}
+		slog.Error("ui host tab: get host", "host_id", hostID, "err", err)
+		stdhttp.Error(w, "internal", stdhttp.StatusInternalServerError)
+		return nil, false
+	}
+	return host, true
 }