feat: YouTube transcripts library UI

frontend/app/(dashboard)/youtube/page.tsx

@@ -0,0 +1,27 @@
+import Link from 'next/link';
+import { ArrowLeft } from 'lucide-react';
+import VideoLibrary from '@/features/youtube/components/VideoLibrary';
+
+const YouTubePage = () => {
+  return (
+    <div className='min-h-screen bg-[#13131b] px-4 py-8'>
+      <div className='mx-auto max-w-5xl'>
+        <div className='mb-6 flex items-center gap-3'>
+          <Link
+            href='/chat'
+            aria-label='Back to chat'
+            className='flex h-8 w-8 items-center justify-center rounded-md text-[#6b6b8a] transition-colors hover:bg-[#1e1e2e] hover:text-[#e4e1ed]'
+          >
+            <ArrowLeft className='h-5 w-5' />
+          </Link>
+          <h1 className='text-xl font-semibold text-[#e4e1ed]'>
+            YouTube Transcripts
+          </h1>
+        </div>
+        <VideoLibrary />
+      </div>
+    </div>
+  );
+};
+
+export default YouTubePage;

frontend/features/chat/components/ChatWindow.tsx

@@ -12,6 +12,7 @@ import {
   Bookmark,
   Volume2,
   Headphones,
+  Video,
   Menu,
   X,
 } from 'lucide-react';
@@ -216,6 +217,14 @@ const ChatWindow = () => {
             >
               <Headphones className='h-4 w-4' />
             </Link>
+            <Link
+              href='/youtube'
+              className='inline-flex h-9 w-9 items-center justify-center rounded-md text-[#6b6b8a] transition-colors hover:bg-[#2a2a3d] hover:text-[#e4e1ed]'
+              aria-label='YouTube Transcripts'
+              title='YouTube Transcripts'
+            >
+              <Video className='h-4 w-4' />
+            </Link>
             <Button
               onClick={resetConversation}
               size='icon'

frontend/features/youtube/components/VideoLibrary.tsx

@@ -0,0 +1,48 @@
+'use client';
+
+import { useVideoTranscripts } from '@/features/youtube/hooks/useYoutube';
+import VideoTranscriptCard from '@/features/youtube/components/VideoTranscriptCard';
+
+const SkeletonCard = () => (
+  <div className='flex animate-pulse flex-col gap-3 rounded-lg border border-[#2a2a3d] bg-[#1a1a2e] p-4'>
+    <div className='h-4 w-3/4 rounded bg-[#2a2a3d]' />
+    <div className='h-3 w-1/3 rounded bg-[#2a2a3d]' />
+    <div className='h-16 rounded bg-[#2a2a3d]' />
+    <div className='h-3 w-1/4 rounded bg-[#2a2a3d]' />
+  </div>
+);
+
+const VideoLibrary = () => {
+  const { data: transcripts, isLoading } = useVideoTranscripts();
+
+  if (isLoading) {
+    return (
+      <div className='grid gap-4 sm:grid-cols-2 lg:grid-cols-3'>
+        {[1, 2, 3].map((i) => (
+          <SkeletonCard key={i} />
+        ))}
+      </div>
+    );
+  }
+
+  if (!transcripts || transcripts.length === 0) {
+    return (
+      <div className='flex flex-col items-center justify-center py-24 text-center'>
+        <p className='text-sm text-[#6b6b8a]'>No saved transcripts yet.</p>
+        <p className='mt-1 text-xs text-[#6b6b8a]'>
+          Share a YouTube link with AXON to summarize and save it here.
+        </p>
+      </div>
+    );
+  }
+
+  return (
+    <div className='grid gap-4 sm:grid-cols-2 lg:grid-cols-3'>
+      {transcripts.map((t) => (
+        <VideoTranscriptCard key={t.id} transcript={t} />
+      ))}
+    </div>
+  );
+};
+
+export default VideoLibrary;

frontend/features/youtube/components/VideoTranscriptCard.tsx

@@ -0,0 +1,178 @@
+'use client';
+
+import { useState } from 'react';
+import { formatDistanceToNow } from 'date-fns';
+import { Trash2, Clock, ChevronDown, ChevronUp, Video } from 'lucide-react';
+import {
+  DialogRoot,
+  DialogPopup,
+  DialogTitle,
+  DialogDescription,
+  DialogClose,
+} from '@/components/ui/dialog';
+import { useDeleteTranscript } from '@/features/youtube/hooks/useYoutube';
+import type { VideoTranscriptOut } from '@/features/youtube/types';
+
+interface VideoTranscriptCardProps {
+  transcript: VideoTranscriptOut;
+}
+
+function formatDuration(seconds: number): string {
+  const h = Math.floor(seconds / 3600);
+  const m = Math.floor((seconds % 3600) / 60);
+  const s = seconds % 60;
+  if (h > 0)
+    return `${h}:${String(m).padStart(2, '0')}:${String(s).padStart(2, '0')}`;
+  return `${m}:${String(s).padStart(2, '0')}`;
+}
+
+const VideoTranscriptCard = ({ transcript }: VideoTranscriptCardProps) => {
+  const [deleteOpen, setDeleteOpen] = useState(false);
+  const [expanded, setExpanded] = useState(false);
+  const { mutate: deleteTranscript, isPending: isDeleting } =
+    useDeleteTranscript();
+
+  const displayTitle = transcript.title ?? transcript.video_id;
+
+  function confirmDelete() {
+    deleteTranscript(transcript.id, { onSuccess: () => setDeleteOpen(false) });
+  }
+
+  const relativeTime = formatDistanceToNow(new Date(transcript.created_at), {
+    addSuffix: true,
+  });
+
+  return (
+    <div className='flex flex-col gap-3 rounded-lg border border-[#2a2a3d] bg-[#1a1a2e] p-4'>
+      {/* Header */}
+      <div className='flex items-start gap-2'>
+        <a
+          href={transcript.youtube_url}
+          target='_blank'
+          rel='noopener noreferrer'
+          className='mt-0.5 shrink-0 text-[#6b6b8a] transition-opacity hover:opacity-75'
+          aria-label='Open on YouTube'
+        >
+          <Video className='h-4 w-4' />
+        </a>
+        <a
+          href={transcript.youtube_url}
+          target='_blank'
+          rel='noopener noreferrer'
+          className='min-w-0 flex-1 text-sm font-medium text-[#e4e1ed] hover:underline'
+          title={displayTitle}
+        >
+          <span className='line-clamp-2'>{displayTitle}</span>
+        </a>
+        <button
+          type='button'
+          onClick={() => setDeleteOpen(true)}
+          disabled={isDeleting}
+          aria-label='Delete transcript'
+          className='flex h-8 w-8 shrink-0 cursor-pointer items-center justify-center rounded-md text-[#6b6b8a] transition-colors hover:bg-[#2a2a3d] hover:text-[#ff6b6b] disabled:cursor-not-allowed disabled:opacity-50'
+        >
+          <Trash2 className='h-4 w-4' />
+        </button>
+      </div>
+
+      {/* Metadata */}
+      {(transcript.channel || transcript.duration_s != null) && (
+        <div className='flex items-center gap-3 text-xs text-[#6b6b8a]'>
+          {transcript.channel && (
+            <span className='truncate'>{transcript.channel}</span>
+          )}
+          {transcript.duration_s != null && (
+            <span className='flex shrink-0 items-center gap-1'>
+              <Clock className='h-3 w-3' />
+              {formatDuration(transcript.duration_s)}
+            </span>
+          )}
+        </div>
+      )}
+
+      {/* Summary */}
+      <div>
+        <p
+          className={`text-xs leading-relaxed text-[#9b9bb8] ${!expanded ? 'line-clamp-3' : ''}`}
+        >
+          {transcript.summary}
+        </p>
+        {transcript.summary.length > 160 && (
+          <button
+            type='button'
+            onClick={() => setExpanded(!expanded)}
+            className='mt-1 flex items-center gap-0.5 text-xs text-[#6b6b8a] hover:text-[#c0c1ff]'
+          >
+            {expanded ? (
+              <>
+                Show less <ChevronUp className='h-3 w-3' />
+              </>
+            ) : (
+              <>
+                Show more <ChevronDown className='h-3 w-3' />
+              </>
+            )}
+          </button>
+        )}
+      </div>
+
+      {/* Key Points */}
+      {transcript.key_points.length > 0 && (
+        <ul className='flex flex-col gap-1'>
+          {transcript.key_points
+            .slice(0, expanded ? undefined : 3)
+            .map((point, i) => (
+              <li
+                key={i}
+                className='flex items-start gap-1.5 text-xs text-[#9b9bb8]'
+              >
+                <span className='mt-1.5 h-1.5 w-1.5 shrink-0 rounded-full bg-[#494bd6]' />
+                {point}
+              </li>
+            ))}
+          {!expanded && transcript.key_points.length > 3 && (
+            <li className='text-xs text-[#6b6b8a]'>
+              +{transcript.key_points.length - 3} more
+            </li>
+          )}
+        </ul>
+      )}
+
+      {/* Footer */}
+      <p className='text-xs text-[#6b6b8a]'>{relativeTime}</p>
+
+      {/* Delete confirmation dialog */}
+      <DialogRoot open={deleteOpen} onOpenChange={setDeleteOpen}>
+        <DialogPopup>
+          <DialogTitle>Delete transcript?</DialogTitle>
+          <DialogDescription>
+            This will permanently delete &ldquo;{displayTitle}&rdquo; and its
+            cross-indexed memory entry. This action cannot be undone.
+          </DialogDescription>
+          <div className='mt-5 flex justify-end gap-2'>
+            <DialogClose
+              render={
+                <button
+                  type='button'
+                  className='cursor-pointer rounded-lg px-4 py-2 text-sm text-[#9b9bb8] transition-colors hover:bg-[#1e1e2e] hover:text-[#e4e1ed]'
+                />
+              }
+            >
+              Cancel
+            </DialogClose>
+            <button
+              type='button'
+              disabled={isDeleting}
+              onClick={confirmDelete}
+              className='cursor-pointer rounded-lg bg-[#ff4444]/10 px-4 py-2 text-sm text-[#ff6b6b] transition-colors hover:bg-[#ff4444]/20 disabled:cursor-not-allowed disabled:opacity-50'
+            >
+              {isDeleting ? 'Deleting…' : 'Delete'}
+            </button>
+          </div>
+        </DialogPopup>
+      </DialogRoot>
+    </div>
+  );
+};
+
+export default VideoTranscriptCard;

frontend/features/youtube/hooks/useYoutube.ts

@@ -0,0 +1,44 @@
+'use client';
+
+import { useEffect, useState } from 'react';
+import { useMutation, useQuery, useQueryClient } from '@tanstack/react-query';
+import { deleteVideoTranscript, listVideoTranscripts } from '@/lib/api';
+import { createClient } from '@/lib/supabase/client';
+import type { VideoTranscriptOut } from '@/features/youtube/types';
+
+// Broad prefix for mutation invalidation — matches all user variants.
+export const VIDEO_TRANSCRIPTS_KEY = ['video-transcripts'] as const;
+
+function videoTranscriptsKey(userId: string) {
+  return ['video-transcripts', userId] as const;
+}
+
+function useUserId(): string {
+  const [userId, setUserId] = useState('');
+  useEffect(() => {
+    createClient()
+      .auth.getSession()
+      .then(({ data }) => setUserId(data.session?.user.id ?? ''));
+  }, []);
+  return userId;
+}
+
+export function useVideoTranscripts() {
+  const userId = useUserId();
+  return useQuery<VideoTranscriptOut[]>({
+    queryKey: videoTranscriptsKey(userId),
+    queryFn: listVideoTranscripts,
+    enabled: !!userId,
+    staleTime: 60_000,
+  });
+}
+
+export function useDeleteTranscript() {
+  const qc = useQueryClient();
+  return useMutation<void, Error, string>({
+    mutationFn: deleteVideoTranscript,
+    onSuccess: () => {
+      void qc.invalidateQueries({ queryKey: VIDEO_TRANSCRIPTS_KEY });
+    },
+  });
+}

frontend/features/youtube/types.ts

@@ -0,0 +1,11 @@
+export interface VideoTranscriptOut {
+  id: string;
+  youtube_url: string;
+  video_id: string;
+  title: string | null;
+  channel: string | null;
+  duration_s: number | null;
+  summary: string;
+  key_points: string[];
+  created_at: string;
+}

frontend/lib/api.ts

@@ -6,6 +6,7 @@ import type {
   SSEEvent,
 } from '@/features/chat/types';
 import type { AudioEntryOut } from '@/features/audio/types';
+import type { VideoTranscriptOut } from '@/features/youtube/types';
 
 const API_BASE = process.env.NEXT_PUBLIC_API_URL ?? 'http://localhost:8000';
 
@@ -260,3 +261,18 @@ export function deleteAudioEntry(id: string): Promise<void> {
     method: 'DELETE',
   });
 }
+
+export function listVideoTranscripts(): Promise<VideoTranscriptOut[]> {
+  return apiFetch<VideoTranscriptOut[]>('/api/v1/youtube');
+}
+
+const _deleteTranscriptSchema = z.object({
+  id: z.string().uuid(),
+});
+
+export function deleteVideoTranscript(id: string): Promise<void> {
+  const { id: validId } = _deleteTranscriptSchema.parse({ id });
+  return apiFetchVoid(`/api/v1/youtube/${encodeURIComponent(validId)}`, {
+    method: 'DELETE',
+  });
+}