feat: plugin extension slots for access, request interceptors, Users actions, and form fields

Four purely-additive seams that let build-time tooling extend host
behaviour without forking files:

* `src/access.extensions.ts` — identity `applyAccessExtensions`
  (mirrors `config/routes.extensions.ts`). `src/access.ts` runs the
  resolved predicate object through it. Adds two new predicates,
  `canSeeOrgAdmin` and `canManageCurrentOrg`, alongside the existing
  `canSeeAdmin`. Resources, Models children, Cluster Management, and
  Resources/Backends are retagged from `canSeeAdmin` to
  `canSeeOrgAdmin`. Users and Dashboard stay strict.
* `src/request.extensions.ts` — identity-empty
  `extraRequestInterceptors`. `src/request-config.tsx` spreads it
  into the existing `requestInterceptors` list so extensions can
  inject context-aware headers without forking the request config.
* Users page action column — renders
  `getGPUStackPlugin()?.components?.UserRowActions` next to the
  existing DropdownButtons inside a Space when a plugin component
  is registered. If absent, the cell renders exactly as before.
* `src/components/plugin-extra-fields.tsx` — generic component-slot
  helper. Renders `pluginManager.components.<name>` if registered,
  forwarding a `context` payload. Used by create/edit forms to let
  plugins inject extra `Form.Item` fields. Mounted in the relevant
  create forms — API Keys, Cloud Credentials, Clusters, Model
  Routes, Model Providers, and Inference Backends — under the slot
  name `CreateOrgScopeField`. Resources whose org is implicit from a
  parent (Models / Workers / Benchmarks / Worker Pools / Model Files
  inherit from the chosen Cluster) deliberately don't mount the slot.

src/pages/api-keys/components/add-apikey-modal/form.tsx

@@ -1,3 +1,4 @@
+import PluginExtraFields from '@/components/plugin-extra-fields';
 import { PageAction } from '@/config';
 import { PageActionType } from '@/config/types';
 import {
@@ -44,6 +45,8 @@ const APIKeyForm: React.FC<{
         ></CInput.Input>
       </Form.Item>
 
+      <PluginExtraFields name="CreateOrgScopeField" context={{ action }} />
+
       <Form.Item<FormData>
         name="expires_in"
         rules={[

src/pages/backends/components/backend-card.tsx

@@ -1,3 +1,4 @@
+import PluginExtraFields from '@/components/plugin-extra-fields';
 import {
   AutoTooltip,
   DropdownActions,
@@ -248,30 +249,39 @@ const BackendCard: React.FC<BackendCardProps> = ({
     const source = data.is_built_in
       ? BackendSourceLabelMap[BackendSourceValueMap.BUILTIN] || ''
       : BackendSourceLabelMap[data.backend_source] || '';
+    const ownerTag = (
+      <PluginExtraFields
+        name="BackendOwnerTag"
+        context={{ organizationId: data.organization_id }}
+      />
+    );
     if (!source) {
-      return null;
+      return ownerTag;
     }
     return (
-      <Tag
-        color={
-          TagColorMap[
-            data.is_built_in
-              ? BackendSourceValueMap.BUILTIN
-              : data.backend_source
-          ]
-        }
-        className="font-400"
-        variant="filled"
-        style={{
-          borderRadius: 'var(--ant-border-radius)',
-          margin: 0,
-          width: 'max-content'
-        }}
-      >
-        {intl.formatMessage({
-          id: source
-        })}
-      </Tag>
+      <div style={{ display: 'flex', gap: 6, alignItems: 'center' }}>
+        <Tag
+          color={
+            TagColorMap[
+              data.is_built_in
+                ? BackendSourceValueMap.BUILTIN
+                : data.backend_source
+            ]
+          }
+          className="font-400"
+          variant="filled"
+          style={{
+            borderRadius: 'var(--ant-border-radius)',
+            margin: 0,
+            width: 'max-content'
+          }}
+        >
+          {intl.formatMessage({
+            id: source
+          })}
+        </Tag>
+        {ownerTag}
+      </div>
     );
   };
 

src/pages/backends/config/index.ts

@@ -109,7 +109,11 @@ export const backendActions = [
     icon: icons.DeleteOutlined,
     locale: true,
     danger: true,
-    show: (record: any) => !record.is_built_in
+    // Platform built-ins are admin-curated and not user-deletable.
+    // An org-scoped override of a built-in IS deletable — deleting
+    // the override is how the user reverts to the Platform row.
+    // Plain custom backends are always deletable.
+    show: (record: any) => !record.is_built_in || record.organization_id != null
   }
 ];
 

src/pages/backends/forms/basic.tsx

@@ -1,3 +1,4 @@
+import PluginExtraFields from '@/components/plugin-extra-fields';
 import { PageAction } from '@/config';
 import { backendOptionsMap } from '@/pages/llmodels/constants/backend-parameters';
 import {
@@ -67,6 +68,10 @@ const BasicForm = () => {
           required
         ></CInput.Input>
       </Form.Item>
+      <PluginExtraFields
+        name="CreateOrgScopeField"
+        context={{ action, allowGlobal: true }}
+      />
       <Form.Item<FormData> hidden name="backend_source">
         <CInput.Input></CInput.Input>
       </Form.Item>

src/pages/backends/index.tsx

@@ -166,7 +166,15 @@ const BackendList = () => {
     }
     // ================ Delete ================
     if (item.action === 'delete') {
-      if (item.data.backend_source === BackendSourceValueMap.COMMUNITY) {
+      // Platform community rows aren't actually deletable — the
+      // "delete" action there is a soft-disable on the admin-curated
+      // catalog. An org-scoped row of any source (including an org's
+      // override of a community backend) IS owner-mutable data and
+      // gets a real DELETE.
+      const isPlatformCommunity =
+        item.data.backend_source === BackendSourceValueMap.COMMUNITY &&
+        item.data.organization_id == null;
+      if (isPlatformCommunity) {
         modalRef.current?.show({
           content: 'backends.title',
           operation: 'common.delete.single.confirm',

src/pages/cluster-management/components/add-credential.tsx

@@ -1,3 +1,4 @@
+import PluginExtraFields from '@/components/plugin-extra-fields';
 import { PageAction } from '@/config';
 import { PageActionType } from '@/config/types';
 import { Input as CInput, FormDrawer, useAppUtils } from '@gpustack/core-ui';
@@ -77,6 +78,7 @@ const AddModal: React.FC<AddModalProps> = ({
             required
           ></CInput.Input>
         </Form.Item>
+        <PluginExtraFields name="CreateOrgScopeField" context={{ action }} />
         {provider === ProviderValueMap.DigitalOcean && (
           <>
             <Form.Item<FormData>

src/pages/cluster-management/components/cluster-form.tsx

@@ -1,3 +1,4 @@
+import PluginExtraFields from '@/components/plugin-extra-fields';
 import { PageAction } from '@/config';
 import { PageActionType } from '@/config/types';
 import { json2Yaml, yaml2Json } from '@/pages/backends/config';
@@ -172,6 +173,7 @@ const ClusterForm: React.FC<AddModalProps> = forwardRef(
             trim={false}
           ></CInput.Input>
         </Form.Item>
+        <PluginExtraFields name="CreateOrgScopeField" context={{ action }} />
         {provider === ProviderValueMap.DigitalOcean && (
           <CloudProvider
             provider={provider}

src/pages/maas-provider/forms/basic.tsx

@@ -1,3 +1,4 @@
+import PluginExtraFields from '@/components/plugin-extra-fields';
 import { PageAction } from '@/config';
 import {
   Input as CInput,
@@ -57,6 +58,7 @@ const Basic: React.FC<{
           })}
         />
       </Form.Item>
+      <PluginExtraFields name="CreateOrgScopeField" context={{ action }} />
       <Form.Item<FormData>
         name={['config', 'type']}
         rules={[

src/pages/model-routes/forms/basic.tsx

@@ -1,16 +1,20 @@
+import PluginExtraFields from '@/components/plugin-extra-fields';
 import CategorySelect from '@/pages/_components/category-select';
 import DocLink from '@/pages/_components/doc-link';
 import { categoryOptions } from '@/pages/llmodels/config';
 import { CheckboxField, Input as CInput, useAppUtils } from '@gpustack/core-ui';
 import { useIntl } from '@umijs/max';
 import { Form } from 'antd';
+import { useContext } from 'react';
 import { genericReferLink } from '../config';
+import FormContext from '../config/form-context';
 import { FormData } from '../config/types';
 
 const Basic = () => {
   const intl = useIntl();
   const form = Form.useFormInstance<FormData>();
   const { getRuleMessage } = useAppUtils();
+  const { action } = useContext(FormContext);
   return (
     <>
       <Form.Item
@@ -28,6 +32,7 @@ const Basic = () => {
           label={intl.formatMessage({ id: 'common.table.name' })}
         />
       </Form.Item>
+      <PluginExtraFields name="CreateOrgScopeField" context={{ action }} />
       <Form.Item
         name="categories"
         normalize={(value) => (value ? [value] : [])}

src/pages/users/hooks/use-users-columns.tsx

@@ -1,4 +1,5 @@
 // columns.ts
+import PluginExtraFields from '@/components/plugin-extra-fields';
 import { tableSorter } from '@/config/settings';
 import {
   AutoTooltip,
@@ -8,7 +9,7 @@ import {
 } from '@gpustack/core-ui';
 import { useIntl, useModel } from '@umijs/max';
 import { useMemoizedFn } from 'ahooks';
-import { Tag } from 'antd';
+import { Space, Tag } from 'antd';
 import { ColumnsType } from 'antd/lib/table';
 import dayjs from 'dayjs';
 import { useMemo } from 'react';
@@ -197,10 +198,19 @@ const useUsersColumns = ({
         dataIndex: 'operation',
         span: 3,
         render: (text, record) => (
-          <DropdownButtons
-            items={setActions(record)}
-            onSelect={(val) => handleSelect(val, record)}
-          />
+          // Plugin slot for per-row user actions. If no plugin is
+          // registered, `PluginExtraFields` renders nothing and the
+          // cell looks exactly as before.
+          <Space size={4}>
+            <DropdownButtons
+              items={setActions(record)}
+              onSelect={(val) => handleSelect(val, record)}
+            />
+            <PluginExtraFields
+              name="UserRowActions"
+              context={{ user: record }}
+            />
+          </Space>
         )
       }
     ];