feat(discovery): acquire recommendations that keep their names

Acquisition ran yt-dlp without --embed-metadata, so every download
arrived untagged. The scanner then stored the video id as the title and
"Unknown Artist" as the artist, the vetted-candidate tag check rejected
the mismatch, and all 18 acquired tracks were hidden and retired.

- Pass --embed-metadata so downloads carry real tags.
- Let a scan take fallback title/artist from the candidate, for sources
  that still ship untagged files.
- Install Deno alongside yt-dlp: YouTube guards some formats with a JS
  challenge yt-dlp must execute, and no other runtime is enabled.
- Dedupe candidates by artist and title. The (source, external_id) key
  misses the same song reaching us under two Deezer release ids.

Also carries the in-flight discovery work this builds on: the
Recommendations page replacing Discover, the discovery source service,
and the acquisition spec tests.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

frontend/src/components/CommandPalette.tsx

@@ -32,7 +32,7 @@ const NAV_COMMANDS: CommandItem[] = [
   { id: 'nav-artists', label: 'Artists', icon: Users, action: () => {}, keywords: ['artists', 'bands'] },
   { id: 'nav-genres', label: 'Genres', icon: Tag, action: () => {}, keywords: ['genres', 'tags', 'categories'] },
   { id: 'nav-vibe', label: 'Vibe', description: 'Endless recommendations', icon: Zap, action: () => {}, keywords: ['vibe', 'recommendations', 'radio'] },
-  { id: 'nav-discover', label: 'Discover', description: 'Browse by genre', icon: Compass, action: () => {}, keywords: ['discover', 'explore'] },
+  { id: 'nav-recommendations', label: 'Found', description: 'Discovered tracks and their fate', icon: Compass, action: () => {}, keywords: ['found', 'discovery', 'recommendations', 'probation', 'new releases'] },
   { id: 'nav-quarantine', label: 'Quarantine', icon: ShieldAlert, action: () => {}, keywords: ['quarantine', 'disliked', 'trash'] },
   { id: 'nav-jobs', label: 'Jobs', description: 'Background tasks', icon: Terminal, action: () => {}, keywords: ['jobs', 'tasks', 'queue'] },
   { id: 'nav-settings', label: 'Settings', icon: Settings, action: () => {}, keywords: ['settings', 'preferences', 'config'] },
@@ -63,7 +63,7 @@ export function CommandPalette({ open, onClose }: CommandPaletteProps) {
             'nav-artists': '/artists',
             'nav-genres': '/genres',
             'nav-vibe': '/vibe',
-            'nav-discover': '/discover',
+            'nav-recommendations': '/recommendations',
             'nav-quarantine': '/quarantine',
             'nav-jobs': '/jobs',
             'nav-settings': '/settings',

frontend/src/components/NavRail.tsx

@@ -35,7 +35,7 @@ const NAV_GROUPS: NavGroup[] = [
     label: 'AI',
     items: [
       { to: '/vibe', icon: Zap, label: 'Vibe' },
-      { to: '/discover', icon: Compass, label: 'Discover' },
+      { to: '/recommendations', icon: Compass, label: 'Found' },
     ],
   },
   {

frontend/src/components/TopBar.tsx

@@ -17,8 +17,8 @@ const PAGE_TITLES: Record<string, string> = {
   '/albums': 'Albums',
   '/artists': 'Artists',
   '/genres': 'Genres',
+  '/recommendations': 'Found',
   '/vibe': 'Vibe',
-  '/discover': 'Discover',
   '/search': 'Search',
   '/settings': 'Settings',
   '/quarantine': 'Quarantine',

frontend/src/components/VibeAura.tsx

@@ -22,9 +22,11 @@ export function VibeAura({ profile, ambient = false }: { profile: VibeProfile; a
   const energy = clamp(profile.energy, 0.5);
   const novelty = clamp(profile.noveltyHunger ?? profile.explorationCoefficient, 0.3);
   const { energyLabel, discoveryLabel } = describeProfile(energy, novelty);
-  // Warm range only (amber → gold → orange). The old 205 base put a teal-blue
-  // glow in a warm brown room, which read as a different app's accent.
-  const hue = Math.round(28 + novelty * 30 - energy * 12);
+  // Hue is discovery alone: ember red when the Vibe stays familiar, gold when it
+  // reaches. Energy is deliberately absent — it already drives four motion
+  // channels below, and mixing it in here cancelled half the novelty swing.
+  // Warm range only; the old 205 base put a teal-blue glow in a warm brown room.
+  const hue = Math.round(15 + novelty * 40);
   const style = {
     '--vibe-hue': String(hue),
     '--vibe-pulse': `${(4.8 - energy * 2.3).toFixed(2)}s`,
@@ -53,13 +55,47 @@ export function VibeAura({ profile, ambient = false }: { profile: VibeProfile; a
   );
 
   if (ambient) {
+    // Displacing clean gradients by animated fractal noise is what separates a
+    // plasma from a blurred blob. baseFrequency is animated in SMIL rather than
+    // CSS because no CSS property reaches inside an SVG filter primitive.
     return (
       <div
-        className="vibe-aura-blob pointer-events-none absolute left-1/2 top-[28%] z-0 h-[190px] w-[230px] -translate-x-1/2 -translate-y-1/2 opacity-40 mix-blend-screen sm:h-[400px] sm:w-[480px] sm:opacity-70"
+        className="vibe-aura-blob pointer-events-none absolute z-0 h-[380px] w-[420px] -translate-x-1/2 -translate-y-1/2 opacity-85 mix-blend-screen sm:h-[560px] sm:w-[660px] sm:opacity-95"
         style={style}
         role="img"
         aria-label={`Current Vibe: ${energyLabel} energy and ${discoveryLabel} discovery`}
-      />
+      >
+        <svg aria-hidden className="absolute h-0 w-0">
+          <filter id="vibe-plasma" x="-30%" y="-30%" width="160%" height="160%">
+            <feTurbulence
+              type="fractalNoise"
+              baseFrequency="0.009 0.014"
+              numOctaves={3}
+              seed={7}
+              result="noise"
+            >
+              <animate
+                attributeName="baseFrequency"
+                dur={`${(18 - energy * 8).toFixed(1)}s`}
+                values="0.009 0.014; 0.021 0.007; 0.009 0.014"
+                repeatCount="indefinite"
+              />
+            </feTurbulence>
+            <feDisplacementMap
+              in="SourceGraphic"
+              in2="noise"
+              scale={String(Math.round(46 + energy * 70))}
+              xChannelSelector="R"
+              yChannelSelector="G"
+            />
+          </filter>
+        </svg>
+        <div className="vibe-aura-stack">
+          <div className="vibe-aura-layer vibe-aura-rays-layer" />
+          <div className="vibe-aura-layer vibe-aura-swirl-layer" />
+          <div className="vibe-aura-layer vibe-aura-core-layer" />
+        </div>
+      </div>
     );
   }