Back up unsaved editor work locally, structure the settings, fix archive accessibility

- The editor keeps unsaved changes in the browser and offers them
  after a crash, a closed tab or an expired session. No timed save on
  the server: every save is a full revision.
- The save status stays visible in narrow windows.
- Settings get a sticky section bar, two folded groups and a save bar
  that stays in view.
- The admin post list fetches terms and images once, not per post.
- Archive post titles are second-level headings, the archive head
  keeps full text contrast, the skip link sits above a sticky header,
  a linked image without alternative text names its link.
- The editor check starts through the dev router like the others.

Co-Authored-By: Claude Fable 5.2 <noreply@anthropic.com>

public/assets/editor.css

@@ -38,6 +38,7 @@ html:has(>.editor-body){overflow:hidden;height:100%}
 .editor-header .secondary{background:transparent;color:#fff;border:1px solid #ffffff4d;font-size:12px;padding:0 13px;min-height:34px;white-space:nowrap}
 .editor-header .secondary:hover:not(:disabled){background:#ffffff1a;border-color:#ffffff99}
 .editor-header .primary{font-size:12px;padding:0 15px;min-height:34px;white-space:nowrap}
+.editor-message.editor-backup{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:8px 16px;background:#eef2ea;color:#1b2a24;border-bottom-color:#cfd8cc}.editor-backup-actions{display:flex;gap:8px;align-items:center}.editor-backup .secondary,.editor-backup .text-button{margin:0;min-height:30px;padding:4px 12px;font-size:12px}
 .editor-message{border-radius:0;background:#fff0e9;color:#873e24;border-bottom:1px solid #e6c3b2;flex-shrink:0;padding:9px 16px;font-size:12px;line-height:1.6}
 .recovery-bar{display:flex;gap:12px;align-items:center;padding:10px 16px;border-bottom:1px solid var(--line);background:#fff;font-size:12px;flex-wrap:wrap}
 .dialog-actions{display:flex;justify-content:flex-end;gap:10px;margin-top:25px}
@@ -277,7 +278,7 @@ html:has(>.editor-body){overflow:hidden;height:100%}
 @media(prefers-reduced-motion:reduce){.ov-insert{transition:none;opacity:1}}
 
 /* ---- narrow screens ---------------------------------------------------------------------- */
-@media(max-width:1100px){.editor-layout{grid-template-columns:290px minmax(0,1fr)}.editor-page-name{width:150px}.save-actions>span{display:none}.viewport-controls button span{display:none}.viewport-controls button{padding:0 9px}}
+@media(max-width:1100px){.editor-layout{grid-template-columns:290px minmax(0,1fr)}.editor-page-name{width:150px}.save-actions>span{font-size:0;max-width:none;white-space:nowrap}.save-actions>span::before{font-size:11px;content:attr(data-short)}.save-actions>span[data-state=dirty]::before{content:'● Ungespeichert';color:#ffcf8a}.save-actions>span[data-state=saving]::before{content:'Speichert …'}.save-actions>span[data-state=conflict]::before{content:'● Konflikt';color:#ffb0a0}.save-actions>span[data-state=saved]::before{content:'Gespeichert'}.save-actions>span[data-state=loading]::before{content:'Lädt …'}.viewport-controls button span{display:none}.viewport-controls button{padding:0 9px}}
 @media(max-width:850px){
   .editor-body{overflow:auto}#editor{height:auto;min-height:100dvh}
   .editor-header{flex-wrap:wrap;height:auto;padding:8px 10px;gap:8px}.editor-page-name{flex:1;width:auto}.viewport-controls{order:6;margin:0}.save-actions{margin-left:auto}