Add page management to the structured editor

Pages can now be reordered, renamed, and have their metadata edited
without touching YAML.

- Up/down arrows next to each page in the /edit list to reorder.
- "Settings" button per page opens /edit/pages/{slug}/settings — a
  form covering name, slug, page width, desktop nav width, mobile
  header, hide desktop nav, center vertically.
- POST /edit/api/pages/{slug}/fields applies metadata changes
  surgically via the existing yaml.Node + atomic-save flow so
  columns/widgets/comments stay untouched.
- POST /edit/api/pages/{slug}/move?dir=up|down swaps adjacent pages.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

internal/glance/glance.go

@@ -454,6 +454,7 @@ func (a *application) server() (func() error, func() error) {
 
 	mux.HandleFunc("GET /edit", a.handleAdminIndex)
 	mux.HandleFunc("GET /edit/pages/{page}", a.handleAdminPage)
+	mux.HandleFunc("GET /edit/pages/{page}/settings", a.handleAdminPageSettings)
 	mux.HandleFunc("GET /edit/pages/{page}/widgets/{col}/{idx}", a.handleAdminWidget)
 
 	mux.HandleFunc("POST /edit/api/pages", a.handleAdminAddPage)
@@ -474,6 +475,8 @@ func (a *application) server() (func() error, func() error) {
 	mux.HandleFunc("POST /edit/api/pages/{page}/columns/{col}/delete", a.handleAdminDeleteColumn)
 	mux.HandleFunc("POST /edit/api/pages/{page}/columns/{col}/move", a.handleAdminMoveColumn)
 	mux.HandleFunc("POST /edit/api/pages/{page}/columns/{col}/size", a.handleAdminColumnSize)
+	mux.HandleFunc("POST /edit/api/pages/{page}/fields", a.handleAdminUpdatePageFields)
+	mux.HandleFunc("POST /edit/api/pages/{page}/move", a.handleAdminMovePage)
 
 	if a.RequiresAuth {
 		mux.HandleFunc("GET /login", a.handleLoginPageRequest)