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/NoteEditorView.vue

@@ -36,6 +36,7 @@ const showPreview = ref(false);
 const sidebarOpen = ref(true);
 const showHistory = ref(false);
 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;
 });
@@ -325,11 +326,14 @@ onUnmounted(() => assist.clearSelection());
         <button v-if="isEditing" class="btn-history" @click="showHistory = true">History</button>
       </div>
       <input
+        ref="titleRef"
         v-model="title"
         type="text"
         placeholder="Title"
         class="title-input"
         @input="markDirty"
+        @keydown.ctrl.s.prevent="save"
+        @keydown.ctrl.e.prevent="tiptapEditor?.commands.focus()"
       />
     </div>
 
@@ -337,7 +341,7 @@ onUnmounted(() => assist.clearSelection());
     <div class="note-body">
 
       <!-- ── Main column ────────────────────────────────────────── -->
-      <div class="note-main">
+      <div class="note-main" @keydown.ctrl.e.prevent="tiptapEditor?.commands.focus()">
         <div class="body-tabs-row">
           <div class="editor-tabs">
             <button :class="['tab', { active: !showPreview }]" @click="showPreview = false">Write</button>
@@ -366,6 +370,7 @@ onUnmounted(() => assist.clearSelection());
               placeholder="Write your note in Markdown..."
               @update:modelValue="onBodyUpdate"
               @selectionChange="onSelectionChange"
+              @escape="titleRef?.focus()"
             />
           </div>
           <div