fix: credit display and top up and other UI display if personal membe… (#8784)

## Summary

Consolidate scattered role checks for credits, top-up, and subscribe
buttons into centralized workspace permissions (canTopUp,
canManageSubscription), ensuring "Add Credits" requires an active
subscription, subscribe buttons only appear when needed, and team
members see appropriately restricted billing UI.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-8784-fix-credit-display-and-top-up-and-other-UI-display-if-personal-membe-3036d73d3650810fbc2de084f738943c)
by [Unito](https://www.unito.io)

src/platform/workspace/composables/useWorkspaceUI.ts

@@ -14,6 +14,7 @@ interface WorkspacePermissions {
   canLeaveWorkspace: boolean
   canAccessWorkspaceMenu: boolean
   canManageSubscription: boolean
+  canTopUp: boolean
 }
 
 /** UI configuration for workspace role */
@@ -44,7 +45,8 @@ function getPermissions(
       canRemoveMembers: false,
       canLeaveWorkspace: false,
       canAccessWorkspaceMenu: false,
-      canManageSubscription: true
+      canManageSubscription: true,
+      canTopUp: true
     }
   }
 
@@ -57,7 +59,8 @@ function getPermissions(
       canRemoveMembers: true,
       canLeaveWorkspace: true,
       canAccessWorkspaceMenu: true,
-      canManageSubscription: true
+      canManageSubscription: true,
+      canTopUp: true
     }
   }
 
@@ -70,7 +73,8 @@ function getPermissions(
     canRemoveMembers: false,
     canLeaveWorkspace: true,
     canAccessWorkspaceMenu: true,
-    canManageSubscription: false
+    canManageSubscription: false,
+    canTopUp: false
   }
 }