feat(frontend): add play, barChart, copy, externalLink, arrowRight icons

Icon library now has 42 named icons. Enables migration of remaining
inline SVGs in validation-tasks, translate, health, assistant pages.

frontend/src/lib/ui/Icon.svelte

@@ -150,6 +150,21 @@
       "M12 16v-4",
       "M12 8h.01",
     ],
+    play: [
+      "M12 22c5.523 0 10-4.477 10-10S17.523 2 12 2 2 6.477 2 12s4.477 10 10 10z",
+      "M10 8l6 4-6 4V8z",
+    ],
+    barChart: ["M12 20V10", "M18 20V4", "M6 20v-4"],
+    copy: [
+      "M20 9h-9a2 2 0 00-2 2v9a2 2 0 002 2h9a2 2 0 002-2v-9a2 2 0 00-2-2z",
+      "M5 15H4a2 2 0 01-2-2V4a2 2 0 012-2h9a2 2 0 012 2v1",
+    ],
+    externalLink: [
+      "M18 13v6a2 2 0 01-2 2H5a2 2 0 01-2-2V8a2 2 0 012-2h6",
+      "M15 3h6v6",
+      "M10 14L21 3",
+    ],
+    arrowRight: ["M5 12h14", "M12 5l7 7-7 7"],
   };
 
   let paths = $derived(iconPaths[name] || iconPaths.dashboard);