feat(models): capability toggles for custom models with upsert and live caps refresh

- AddCustomModelModal lets users pick vision/reasoning caps when adding a model
- POST /api/models/custom whitelists caps to booleans
- aliasRepo.addCustomModel upserts — re-adding updates caps/name in place
- /api/models includes custom llm models with stored caps overriding the heuristic
- useModelCaps refetches on customModelChanged instead of trusting a stale cache

Co-Authored-By: Claude Code <noreply@anthropic.com>

src/app/(dashboard)/dashboard/providers/[id]/AddCustomModelModal.js

@@ -2,17 +2,21 @@
 
 import { useState, useEffect } from "react";
 import PropTypes from "prop-types";
-import { Button, Modal } from "@/shared/components";
+import { Button, Modal, Toggle } from "@/shared/components";
+import { CAPACITY_META } from "@/shared/constants/models";
+
+const defaultCaps = () => Object.fromEntries(Object.keys(CAPACITY_META).map((key) => [key, false]));
 
 export default function AddCustomModelModal({ isOpen, providerAlias, providerDisplayAlias, onSave, onClose }) {
   const [modelId, setModelId] = useState("");
+  const [caps, setCaps] = useState(defaultCaps);
   const [testStatus, setTestStatus] = useState(null); // null | "testing" | "ok" | "error"
   const [testError, setTestError] = useState("");
   const [saving, setSaving] = useState(false);
 
   // Reset state when modal opens
   useEffect(() => {
-    if (isOpen) { setModelId(""); setTestStatus(null); setTestError(""); }
+    if (isOpen) { setModelId(""); setCaps(defaultCaps()); setTestStatus(null); setTestError(""); }
   }, [isOpen]);
 
   // Strip provider's own alias prefix (e.g. "cc/model" -> "model" for cc provider)
@@ -46,7 +50,7 @@ export default function AddCustomModelModal({ isOpen, providerAlias, providerDis
     if (!cleanId || saving) return;
     setSaving(true);
     try {
-      await onSave(cleanId);
+      await onSave(cleanId, caps);
     } finally {
       setSaving(false);
     }
@@ -86,6 +90,22 @@ export default function AddCustomModelModal({ isOpen, providerAlias, providerDis
           </p>
         </div>
 
+        <div>
+          <label className="text-sm font-medium mb-1.5 block">Capabilities</label>
+          <div className="flex flex-wrap gap-4">
+            {Object.entries(CAPACITY_META).map(([key, meta]) => (
+              <Toggle
+                key={key}
+                checked={!!caps[key]}
+                onChange={(v) => setCaps((prev) => ({ ...prev, [key]: v }))}
+                label={meta.label}
+                description={meta.desc}
+                size="sm"
+              />
+            ))}
+          </div>
+        </div>
+
         {/* Test result */}
         {testStatus === "ok" && (
           <div className="flex items-center gap-2 text-sm text-green-600">

src/app/(dashboard)/dashboard/providers/[id]/page.js

@@ -527,12 +527,12 @@ export default function ProviderDetailPage() {
     }
   };
 
-  const handleAddCustomModel = async (modelId, type = "llm", providerAliasOverride = providerStorageAlias) => {
+  const handleAddCustomModel = async (modelId, type = "llm", providerAliasOverride = providerStorageAlias, caps) => {
     try {
       const res = await fetch("/api/models/custom", {
         method: "POST",
         headers: { "Content-Type": "application/json" },
-        body: JSON.stringify({ providerAlias: providerAliasOverride, id: modelId, type }),
+        body: JSON.stringify({ providerAlias: providerAliasOverride, id: modelId, type, ...(caps ? { caps } : {}) }),
       });
       if (res.ok) {
         await fetchCustomModels();
@@ -1781,8 +1781,8 @@ export default function ProviderDetailPage() {
           isOpen={showAddCustomModel}
           providerAlias={providerStorageAlias}
           providerDisplayAlias={providerDisplayAlias}
-          onSave={async (modelId) => {
-            await handleAddCustomModel(modelId, "llm", providerStorageAlias);
+          onSave={async (modelId, caps) => {
+            await handleAddCustomModel(modelId, "llm", providerStorageAlias, caps);
             setShowAddCustomModel(false);
           }}
           onClose={() => setShowAddCustomModel(false)}