Source picker: rename Soulseek icon to "Basic Search"

That source icon hits /api/search — raw slskd file results, the same
flow the UI historically labelled "Basic Search" before the source-icon
row replaced the dropdown. Reverting the label avoids implying it
returns Soulseek-flavoured metadata results in the same shape as the
other source icons.

Backend route + endpoint name unchanged; this is display-only.

webui/static/shared-helpers.js

@@ -72,8 +72,9 @@ const SOURCE_LABELS = {
         tabClass: 'enh-tab-youtube', badgeClass: 'enh-badge-youtube',
     },
     soulseek: {
-        // No canonical brand logo available — stick with a basic music glyph.
-        text: 'Soulseek', icon: '🎼',
+        // Routes through /api/search (raw slskd file results) — historically
+        // called "Basic Search" in the UI before the source picker landed.
+        text: 'Basic Search', icon: '🎼',
         tabClass: 'enh-tab-soulseek', badgeClass: 'enh-badge-soulseek',
     },
 };