feat: invite member upsell for single-seat plans (#8801)

## Summary

- Show an upsell dialog when single-seat plan users try to invite
members, with a banner on the members panel directing them to upgrade.
- Misc fixes for member max seat display

## Changes

- **What**: `InviteMemberUpsellDialogContent.vue`,
`MembersPanelContent.vue`, `WorkspacePanelContent.vue`

## Screenshots

<img width="2730" height="1907" alt="image"
src="https://github.com/user-attachments/assets/e39a23be-8533-4ebb-a4ae-2797fc382bc2"
/>
<img width="2730" height="1907" alt="image"
src="https://github.com/user-attachments/assets/bec55867-1088-4d3a-b308-5d5cce64c8ae"
/>



┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-8801-feat-invite-member-upsell-for-single-seat-plans-3046d73d365081349b09fe1d4dc572e8)
by [Unito](https://www.unito.io)

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>
Co-authored-by: GitHub Action <action@github.com>

src/platform/workspace/api/workspaceApi.ts

@@ -239,15 +239,6 @@ interface CreateTopupResponse {
   amount_cents: number
 }
 
-interface TopupStatusResponse {
-  topup_id: string
-  status: TopupStatus
-  amount_cents: number
-  error_message?: string
-  created_at: string
-  completed_at?: string
-}
-
 type BillingOpStatus = 'pending' | 'succeeded' | 'failed'
 
 export interface BillingOpStatusResponse {
@@ -701,23 +692,6 @@ export const workspaceApi = {
     }
   },
 
-  /**
-   * Get top-up status
-   * GET /api/billing/topup/:id
-   */
-  async getTopupStatus(topupId: string): Promise<TopupStatusResponse> {
-    const headers = await getAuthHeaderOrThrow()
-    try {
-      const response = await workspaceApiClient.get<TopupStatusResponse>(
-        api.apiURL(`/billing/topup/${topupId}`),
-        { headers }
-      )
-      return response.data
-    } catch (err) {
-      handleAxiosError(err)
-    }
-  },
-
   /**
    * Get billing events
    * GET /api/billing/events

src/platform/workspace/composables/useInviteUrlLoader.test.ts

@@ -130,8 +130,13 @@ describe('useInviteUrlLoader', () => {
       expect(mockToastAdd).toHaveBeenCalledWith({
         severity: 'success',
         summary: 'Invite Accepted',
-        detail: 'You have been added to Test Workspace',
-        life: 5000
+        detail: {
+          text: 'You have been added to Test Workspace',
+          workspaceId: 'ws-123',
+          workspaceName: 'Test Workspace'
+        },
+        group: 'invite-accepted',
+        closable: true
       })
     })
 

src/platform/workspace/composables/useInviteUrlLoader.ts

@@ -81,12 +81,17 @@ export function useInviteUrlLoader() {
       toast.add({
         severity: 'success',
         summary: t('workspace.inviteAccepted'),
-        detail: t(
-          'workspace.addedToWorkspace',
-          { workspaceName: result.workspaceName },
-          { escapeParameter: false }
-        ),
-        life: 5000
+        detail: {
+          text: t(
+            'workspace.addedToWorkspace',
+            { workspaceName: result.workspaceName },
+            { escapeParameter: false }
+          ),
+          workspaceName: result.workspaceName,
+          workspaceId: result.workspaceId
+        },
+        group: 'invite-accepted',
+        closable: true
       })
     } catch (error) {
       toast.add({