feat(workspace): sliding sidebar in focus mode, calmer workspace bar, smoother journal

- focus mode: folders slide in from the left (button, title click, or the
  left edge on wide screens); picking a note keeps focus mode
- workspace bar: borderless live/shared/save pills in one style, divider
  before the note actions; footer without top line
- journal panel and calendar open with an animation, the view fades in
- paste and markdown import nest a list under the paragraph introducing it

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

frontend/src/index.css

@@ -583,3 +583,15 @@ fieldset:disabled :is(button, input, select, textarea) {
 @media (prefers-reduced-motion: reduce) {
   .focus-mode-enter { animation: none; }
 }
+
+/* Views that replace each other (journal ↔ note) fade in instead of jumping */
+@keyframes view-in {
+  from { opacity: 0; transform: translateY(6px); }
+  to { opacity: 1; transform: none; }
+}
+.view-enter {
+  animation: view-in 280ms ease-out;
+}
+@media (prefers-reduced-motion: reduce) {
+  .view-enter { animation: none; }
+}