Fix unreadable user markdown colors and truncate long texts in deletion dialogs (#17555)

* webui: limit conversation name length in dialogs

* webui: fix unreadable colors on links and table cell hover in user markdown

* webui: keep table borders visible in user markdown

* webui: updating unified exports

* Update tools/server/webui/src/lib/components/app/chat/ChatAttachments/ChatAttachmentThumbnailFile.svelte

Co-authored-by: Aleksander Grygier <aleksander.grygier@gmail.com>

* chore: update webui build output

* chore: update webui build output

* chore: update webui build output

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Co-authored-by: Aleksander Grygier <aleksander.grygier@gmail.com>

tools/server/webui/src/lib/utils/text.ts

@@ -0,0 +1,7 @@
+/**
+ * Returns a shortened preview of the provided content capped at the given length.
+ * Appends an ellipsis when the content exceeds the maximum.
+ */
+export function getPreviewText(content: string, max = 150): string {
+	return content.length > max ? content.slice(0, max) + '...' : content;
+}