feel: card resting spacing + editor Cmd/Ctrl+Enter

- NoteCard: overlay the hover toolbar (absolute bottom-right, translucent
  backdrop, pointer-events gated) instead of reserving a permanent action row.
  At rest cards are now content-sized with even padding, so text no longer
  looks pinned to the top above an empty strip. Affects every card surface
  (board, search, graph, reminders).
- NoteEditor: Cmd/Ctrl+Enter saves & closes (mirrors Esc-closes).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FRgehjoz7Yv8LkUfADxACm

frontend/src/components/NoteCard.vue

@@ -105,8 +105,11 @@ function cardClass(color: NoteColor): string {
       </span>
     </div>
 
+    <!-- Toolbar overlays the card's bottom-right on hover/focus instead of
+         reserving a permanent row — so at rest the card is content-sized with
+         even padding, not text pinned to the top above an empty strip. -->
     <div
-      class="mt-2 flex items-center justify-end gap-0.5 opacity-0 transition focus-within:opacity-100 group-hover:opacity-100"
+      class="pointer-events-none absolute bottom-1.5 right-1.5 flex items-center gap-0.5 rounded-lg bg-white/85 p-0.5 opacity-0 shadow-sm ring-1 ring-black/5 backdrop-blur-sm transition focus-within:pointer-events-auto focus-within:opacity-100 group-hover:pointer-events-auto group-hover:opacity-100 dark:bg-neutral-900/85 dark:ring-white/10"
     >
       <template v-if="note.trashed">
         <button type="button" class="icon-btn" title="Restore" aria-label="Restore" @click="notes.restore(note.id)">

frontend/src/components/NoteEditor.vue

@@ -182,6 +182,8 @@ async function act(fn: () => Promise<void>) {
       role="dialog"
       aria-modal="true"
       @keydown.esc="close"
+      @keydown.enter.meta.prevent="close"
+      @keydown.enter.ctrl.prevent="close"
       @paste="onPaste"
     >
       <div class="flex flex-col gap-2 p-4">