A host from the web site; the same page kept once; deleting from the Notebooks chooser

From the development repository at 299f73d, 2026-10-11:
hosting from the site documented; a page loaded from a notebook and left
unchanged is not kept again; notebooks and pages are deleted from the
chooser, to the system's Trash (--trash); the Notebooks button.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

client/index.html

@@ -93,7 +93,7 @@
       <button id="load_image" type="button"
               data-help="Put an image file, such as a scanned exercise, on the page for everyone: below the images already there, centred, at its own size. Rest the pen on an image to move it, or near a corner to scale it; it comes to the front. A tap of the eraser on an image removes it; writing on it stays.">Image</button>
       <button id="load_notebook_page" type="button"
-              data-help="Start a new page for everyone from a page kept in a notebook, with everything on it. The current page is kept in each notebook.">Notebook</button>
+              data-help="Start a new page for everyone from a page kept in a notebook, with everything on it. The current page is kept in each notebook.">Notebooks</button>
     </div>
     <div class="group" aria-label="Notebook">
       <select id="session_notebook" class="notebook_pick" aria-label="Current notebook"
@@ -152,6 +152,8 @@
 <dialog id="notebook_chooser" class="chooser">
   <header>
     <h2>Notebooks</h2>
+    <button id="chooser_delete" type="button" class="delete" hidden
+            data-help="Delete the marked notebooks and pages. The first press says what will happen; the second does it.">Delete</button>
     <button id="chooser_close" type="button" aria-label="Close">×</button>
   </header>
   <div class="chooser_body">