fix(provider): split partial model fetch warnings from errors

frontend/src/features/providers/components/EndpointFormDialog.vue

@@ -154,7 +154,6 @@
                     <Input
                       :model-value="getDisplayedPath(endpoint)"
                       :placeholder="getEndpointDefaultPath(endpoint) || '留空使用默认'"
-                      :disabled="isFixedProvider"
                       @update:model-value="(v) => updateEndpointField(endpoint.id, 'path', v)"
                     />
                     <p
@@ -1878,9 +1877,6 @@ function getEndpointDefaultPath(endpoint: ProviderEndpoint): string {
 }
 
 function getDisplayedPath(endpoint: ProviderEndpoint): string {
-  if (isFixedProvider.value) {
-    return getDefaultPath(endpoint.api_format, endpoint.base_url)
-  }
   return getEndpointEditState(endpoint.id)?.path ?? (endpoint.custom_path || '')
 }
 
@@ -3217,13 +3213,13 @@ async function saveEndpoint(endpoint: ProviderEndpoint) {
 
   savingEndpointId.value = endpoint.id
   try {
-    // 仅提交变更字段，避免 fixed provider 因 base_url/custom_path 被锁定而更新失败
+    // 仅提交变更字段；fixed provider 锁定 base_url，但允许覆盖 custom_path。
     const payload: Record<string, unknown> = {}
 
     if (!isFixedProvider.value) {
       if (state.url !== endpoint.base_url) payload.base_url = state.url
-      if (state.path !== (endpoint.custom_path || '')) payload.custom_path = state.path || null
     }
+    if (state.path !== (endpoint.custom_path || '')) payload.custom_path = state.path || null
 
     if (hasRulesChanges(endpoint)) payload.header_rules = rulesToHeaderRules(state.rules)
     if (hasResponseHeaderRulesChanges(endpoint)) {