fix(dashboard): show custom provider_nodes providers in the Topology view instead of only AI_PROVIDERS (#8328) (#8357)

src/shared/utils/providerFallbackColor.ts

@@ -0,0 +1,41 @@
+/**
+ * Deterministic fallback color for provider ids that are not present in the static
+ * AI_PROVIDERS registry — e.g. user-defined `openai-compatible-*` / `anthropic-compatible-*`
+ * providers backed by the `provider_nodes` table. Without this, every such custom provider
+ * rendered as the same anonymous gray node in the Topology view, indistinguishable from any
+ * other custom provider even though its label was already resolved correctly. See #8328.
+ */
+
+// Small palette of visually distinguishable, saturated colors — spread far enough apart in
+// hue to stay distinguishable side-by-side on both light and dark topology backgrounds.
+export const FALLBACK_COLOR_PALETTE: readonly string[] = [
+  "#0ea5e9", // sky
+  "#a855f7", // purple
+  "#f59e0b", // amber
+  "#10b981", // emerald
+  "#ec4899", // pink
+  "#6366f1", // indigo
+  "#14b8a6", // teal
+  "#f97316", // orange
+];
+
+/** FNV-1a hash — fast, deterministic, and well-distributed for short id strings. */
+function hashProviderId(value: string): number {
+  let hash = 0x811c9dc5;
+  for (let i = 0; i < value.length; i++) {
+    hash ^= value.charCodeAt(i);
+    hash = Math.imul(hash, 0x01000193);
+  }
+  return hash >>> 0;
+}
+
+/**
+ * Returns a deterministic color for a provider id not present in the static AI_PROVIDERS
+ * registry: the same id always maps to the same palette entry, and different ids spread
+ * across the palette so distinct custom providers stay visually distinguishable.
+ */
+export function getFallbackProviderColor(providerId: string): string {
+  if (!providerId) return FALLBACK_COLOR_PALETTE[0];
+  const index = hashProviderId(providerId) % FALLBACK_COLOR_PALETTE.length;
+  return FALLBACK_COLOR_PALETTE[index];
+}