fix(models): show custom provider models in combo picker

Merge customModels from /api/models/custom into the isCustomProvider
branch so custom compatible providers display imported models instead
of the prefix/model-id placeholder. Mirrors the passthrough pattern;
filter by providerId since providerAlias stores the raw provider ID.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/shared/components/ModelSelectModal.js

@@ -249,9 +249,22 @@ export default function ModelSelectModal({
             value: `${nodePrefix}/${fullModel.replace(`${providerId}/`, "")}`,
           }));
 
+        // Merge custom models registered via /api/models/custom for this provider
+        // providerAlias in DB uses the raw providerId, not the display prefix
+        const registeredCustom = customModels
+          .filter((m) => m.providerAlias === providerId)
+          .map((m) => ({
+            id: m.id,
+            name: m.name || m.id,
+            value: `${nodePrefix}/${m.id}`,
+            isCustom: true,
+          }));
+        const seen = new Set(nodeModels.map((m) => m.value));
+        const mergedModels = [...nodeModels, ...registeredCustom.filter((m) => !seen.has(m.value))];
+
         // Always show compatible providers that are connected, even with no aliases.
         // When no aliases exist, show a placeholder so users know it's available.
-        const modelsToShow = nodeModels.length > 0 ? nodeModels : [{
+        const modelsToShow = mergedModels.length > 0 ? mergedModels : [{
           id: `__placeholder__${providerId}`,
           name: `${nodePrefix}/model-id`,
           value: `${nodePrefix}/model-id`,
@@ -264,7 +277,7 @@ export default function ModelSelectModal({
           color: providerInfo.color,
           models: modelsToShow,
           isCustom: true,
-          hasModels: nodeModels.length > 0,
+          hasModels: mergedModels.length > 0,
         };
       } else {
         const hardcodedModels = getModelsByProviderId(providerId);