Article editor toolbar: toggling fences/links, class pickers, sizes, Tab indent

- Image insert always adds an empty "" caption with the cursor inside.
- Fenced blocks (``` code, ::: aside) share one toggle: clicked inside
  one it is removed and the content selected; otherwise the selection
  (expanded to whole lines) is wrapped, cursor left on the opener line.
- Code button: inline wrap toggles (selection preserved, backtick runs),
  line-spanning selections make fenced blocks.
- Link button toggles: clicked inside [label](url) it unwraps.
- Block classes via two pickers (placement, AA size) with current-class
  indication and a "normal" reset; placement replaces ::: container
  names, fences get their own attribute line.
- New .small/.large/.huge text-size classes (0.7/1.5/3em); base body is
  exactly 1rem so the scale is uniform.
- .left/.right floats generalized from figures to any block.
- Toolbar polish: non-emoji glyphs, scaled-up symbols, borderless
  hover/active states, reordered (B/i and size last).
- Editor panel no longer closes on Escape.
- CodeMirror editors capture Tab/Shift-Tab for indent/dedent.

frontend/src/EditorShell.vue

@@ -54,20 +54,16 @@ function onSwitchEvent(ev) {
 // Closing the shell hides it but keeps it mounted (main.js); the tabs stay
 // cached in KeepAlive the whole time, so no state is ever lost until a real
 // page reload. On re-show each active tab re-applies its window title and
-// preview via its own pagerite:editor-shown listener.
-function onKeydown(ev) {
-  if (ev.key === 'Escape' && document.body.classList.contains('editing')) close()
-}
+// preview via its own pagerite:editor-shown listener. No Escape-to-close:
+// it fired too easily by accident (e.g. dismissing an editor popup).
 
 onMounted(() => {
   document.body.dataset.editorMode = activeMode.value
   addEventListener('pagerite:switch-editor', onSwitchEvent)
-  addEventListener('keydown', onKeydown)
 })
 
 onUnmounted(() => {
   removeEventListener('pagerite:switch-editor', onSwitchEvent)
-  removeEventListener('keydown', onKeydown)
 })
 </script>