Move pages to and from the vault

A page, including a journal day, can be moved into the unlocked vault with its id kept. Links to it elsewhere become [[locked:id]], shown as Locked Page until the vault is unlocked, so its title is kept only in the vault. Move out reverses it.

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

README.md

@@ -36,7 +36,9 @@ Named for the mako shark, the fastest in the sea, because a notebook should keep
 - **A vault for what needs more.** Pages in the Vault open only with a passphrase of their own, on top of
   signing in. The server cannot read them until you unlock it, and they are in no list, search or download
   of your ordinary notebook. It locks itself after 15 minutes idle, when you press Lock, and when you
-  sign out. See Encryption below.
+  sign out. See Encryption below. Press To vault on any page, journal days included, and Move out on a
+  vault page to bring it back. A page that links to a vaulted page shows Locked Page in its place until
+  you unlock the vault, and the vaulted page's title is kept only in the vault.
 - **Take it with you.** Download everything as a zip that opens as a vault in Obsidian: file names are
   titles, so the links keep working, and journal days sit in a Journal folder.
 
@@ -200,8 +202,10 @@ file time as its date, and is then encrypted (name it with lower-case letters, n
 - Searching holds every page in memory, which is comfortable for tens of thousands of pages and not
   built for millions.
 - Pages are only reloaded from disk when Mako starts.
-- The Vault has its own pages only: no links into or out of it, no tags, no journal, and it is not in the
-  zip download. You cannot change its passphrase yet.
+- A page in the Vault cannot link to your ordinary pages or use their tags, and the vault is not in the zip
+  download. Moving a page in takes its subpages up a level but does not move them with it, and a journal day
+  moved in leaves that day empty, so starting it again makes a new page which cannot be moved in while
+  the first is there. You cannot change its passphrase yet.
 - Live preview works a line at a time (a code block counts as one), so a table or a quote spread over
   several lines shows rendered line by line. View shows the whole page as one. Selecting across lines
   (Ctrl+A, Shift+Up or Down, Shift+click, or dragging) opens those whole lines as raw markdown, so a