Show a progress bar and live log while Hammerhead, edges and sites update

The updater reports each step (checking, downloading with percent, verifying, installing, restarting).
Edges and sites send that progress and their log with their reports; Hammerhead serves it to a dialog
that opens when an update starts, and keeps its own last update log on disk across the restart.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

store.go

@@ -209,6 +209,8 @@ type Server struct {
 	oidc    map[string]*oidcDoc
 
 	alerts   map[string]*alertState // active problems by key (see alerts.go)
+	updRuns  map[string]*updRun     // progress of updates running on edges and sites, by ID
+	selfUpd  selfUpdate             // progress of this server's own update
 	verMu    sync.Mutex             // guards verCache and verAt, the latest releases seen by /api/versions
 	verCache map[string]string
 	verAt    time.Time
@@ -253,6 +255,7 @@ func New(dir string, opts Options) (*Server, error) {
 		oidc:       map[string]*oidcDoc{},
 		alerts:     map[string]*alertState{},
 		mtaSent:    map[string]time.Time{},
+		updRuns:    map[string]*updRun{},
 	}
 	s.st.Sessions = map[string]*Session{}
 	s.st.Secrets = map[string]*Secret{}
@@ -282,6 +285,7 @@ func New(dir string, opts Options) (*Server, error) {
 	if opts.SelfDomain != "" && opts.SelfTunnel == "" {
 		s.opts.SelfTunnel = opts.SelfDomain + ":51820"
 	}
+	s.finishSelfUpdateLog()
 	if err := s.ensureSelfEdge(); err != nil {
 		db.Close()
 		return nil, err