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/components/TiptapEditor.vue

@@ -24,6 +24,7 @@ const props = withDefaults(
 const emit = defineEmits<{
   "update:modelValue": [value: string];
   selectionChange: [payload: { text: string; start: number; end: number }];
+  escape: [];
 }>();
 
 let updatingFromProp = false;
@@ -41,6 +42,14 @@ try {
     content: markdownToHtml(props.modelValue),
     editable: true,
     editorProps: {
+      handleKeyDown: (_view, event) => {
+        if (event.key === "Escape") {
+          editor?.commands.blur();
+          emit("escape");
+          return true;
+        }
+        return false;
+      },
       handlePaste: (_view, event) => {
         const text = event.clipboardData?.getData("text/plain");
         if (!text || !editor) return false;