Keyboard navigation improvements across all editors

TiptapEditor.vue (central — applies to all three editors):
- Escape inside editor blurs it and emits 'escape' event to parent

TagInput.vue (central — applies everywhere tags are used):
- ArrowUp/ArrowDown navigate autocomplete suggestion list with visual highlight
- Enter confirms the keyboard-selected suggestion instead of typed text

NoteEditorView, TaskEditorView, WorkspaceNoteEditor (per-editor wiring):
- @escape on TiptapEditor returns focus to the title input (ref="titleRef")
- Ctrl+E from title input or editor main column jumps focus into editor body
- Ctrl+S on title input saves (was already on editor area; now consistent)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/views/TaskEditorView.vue

@@ -100,6 +100,7 @@ async function toggleSubTask(sub: SubTask) {
 const showPreview = ref(true);
 const sidebarOpen = ref(true);
 const editorRef = ref<InstanceType<typeof TiptapEditor> | null>(null);
+const titleRef = ref<HTMLInputElement | null>(null);
 const tiptapEditor = computed<Editor | null>(() => {
   return (editorRef.value?.editor as Editor | undefined) ?? null;
 });
@@ -392,8 +393,11 @@ useEditorGuards(dirty, save);
         v-model="title"
         type="text"
         placeholder="Task title"
+        ref="titleRef"
         class="title-input"
         @input="markDirty"
+        @keydown.ctrl.s.prevent="save"
+        @keydown.ctrl.e.prevent="tiptapEditor?.commands.focus()"
       />
 
     </div><!-- /editor-header: title only -->
@@ -402,7 +406,7 @@ useEditorGuards(dirty, save);
     <div class="task-body">
 
       <!-- ── Main column ─────────────────────────────────────────── -->
-      <div class="task-main">
+      <div class="task-main" @keydown.ctrl.e.prevent="tiptapEditor?.commands.focus()">
 
         <!-- Write / Preview tabs + toolbar sit above the editor -->
         <div class="body-tabs-row">
@@ -434,6 +438,7 @@ useEditorGuards(dirty, save);
             placeholder="Describe this task..."
             @update:modelValue="onBodyUpdate"
             @selectionChange="onSelectionChange"
+            @escape="titleRef?.focus()"
           />
         </div>
         <div