cover logo: bump the cache recipe for the ink-scaled alpha ramp

Every persisted mask predates the anti-aliasing the trace path now relies on,
so without this bump a cached artist keeps rendering from a near-binary mask
while the tracer runs at the lighter blur that assumes real gradients -- the
worst of both. The key already hashes the recipe, so old entries simply miss.

src-tauri/src/commands.rs

@@ -1542,7 +1542,9 @@ pub async fn catalog_artist_socials(
     Ok(state.metadata.catalog_artist_socials(artist_id).await)
 }
 
-const COVER_LOGO_RECIPE: &str = "cover-logo-perf-v3-identity";
+// v4: the alpha ramp now scales to the measured ink distance, so every cached
+// mask predates the anti-aliasing this pipeline relies on and must be redrawn.
+const COVER_LOGO_RECIPE: &str = "cover-logo-v4-ink-scaled-alpha";
 const COVER_LOGO_MAX_COVERS: usize = 14;
 const COVER_LOGO_MAX_HITS: usize = 5;
 const COVER_LOGO_LOCATE_WINDOW: usize = 4;