fix(hover-card): maiden name false positive, placeholder on non-empty editor, card persistence

- PersonHoverCard: alias is compared against both `lastName` and `displayName`
  before showing as maiden name — prevents false positive when alias is stored
  as the full current name (e.g. "Maria Schmidt" ≠ "Schmidt" but name unchanged)
- PersonMentionEditor: data-placeholder was set statically so the CSS ::before
  rule showed the placeholder on any blur even with content; now a $effect
  toggles the attribute based on editor.isEmpty
- TranscriptionReadView: hovering onto the card itself cancels the 150ms close
  timer so the card stays open while reading it; leaving the card closes it
  immediately — onmouseenter/onmouseleave wired through PersonHoverCard props
- hoverCardPosition: removed scrollX/scrollY offset since the card is now
  position:fixed (scroll is already baked into getBoundingClientRect coords)
- MentionDropdown: raised z-index from z-20 to z-50 to render above the hover card
- vite.config.ts: pre-bundle Tiptap packages to avoid HMR waterfall on first load

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

frontend/src/lib/components/TranscriptionReadView.svelte

@@ -93,13 +93,28 @@ function getOrFetchHoverData(personId: string): Promise<HoverData | null> {
 function currentViewport() {
 	return {
 		viewportWidth: window.innerWidth,
-		viewportHeight: window.innerHeight,
-		scrollX: window.scrollX,
-		scrollY: window.scrollY
+		viewportHeight: window.innerHeight
 	};
 }
 
+let closeTimer: ReturnType<typeof setTimeout> | null = null;
+
+function scheduleCardClose() {
+	closeTimer = setTimeout(() => {
+		activeCard = null;
+		closeTimer = null;
+	}, 150);
+}
+
+function cancelCardClose() {
+	if (closeTimer !== null) {
+		clearTimeout(closeTimer);
+		closeTimer = null;
+	}
+}
+
 async function handleMentionEnter(event: Event) {
+	cancelCardClose();
 	const link = event.target as HTMLAnchorElement;
 	const personId = link.dataset.personId;
 	if (!personId) return;
@@ -140,7 +155,11 @@ async function handleMentionEnter(event: Event) {
 function handleMentionLeave(event: Event) {
 	const link = event.target as HTMLAnchorElement;
 	link.removeAttribute('aria-describedby');
-	activeCard = null;
+	if (event.type === 'mouseleave') {
+		scheduleCardClose();
+	} else {
+		activeCard = null;
+	}
 }
 
 /**
@@ -231,6 +250,8 @@ function attachMentionHandlers(node: HTMLElement) {
 		cardId={activeCard.cardId}
 		position={activeCard.position}
 		state={activeCard.state}
+		onmouseenter={cancelCardClose}
+		onmouseleave={() => { activeCard = null; }}
 	/>
 {/if}