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>

internal/web/static/style.css

@@ -347,3 +347,5 @@
   .vault-row:hover { background:var(--accent-soft); }
   .vault-name { display:flex; align-items:center; gap:var(--s2); flex:1; min-width:0; color:var(--text); text-decoration:none; }
   .clip1 { overflow:hidden; text-overflow:ellipsis; white-space:nowrap; }
+  .wikilink .icon { vertical-align:-2px; margin-right:var(--s1); }
+  .wikilink.locked { color:var(--text-muted); border-bottom-style:dotted; border-bottom-color:var(--text-faint); }