fix: allow join with pending invitation for restricted rooms

Remove premature check that blocked access to restricted rooms. Now:
- Frontend no longer blocks restricted room access upfront
- Backend API checks for pending invitation
- Users with valid invitations can join successfully
- Users without invitations get appropriate error message

This fixes the issue where users with pending invitations couldn't join
restricted rooms via the join link.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

apps/web/src/app/join/[code]/page.tsx

@@ -277,21 +277,17 @@ export default function JoinRoomPage({ params }: { params: { code: string } }) {
           return
         }
 
-        if (room.accessMode === 'restricted') {
-          setError('This room is invitation-only')
-          return
-        }
-
         if (room.accessMode === 'approval-only') {
           setShowApprovalPrompt(true)
           return
         }
 
+        // For restricted rooms, try to join - the API will check for invitation
         // If user is in a different room, show confirmation
         if (roomData) {
           setShowConfirmation(true)
         } else {
-          // Otherwise, auto-join (for open rooms)
+          // Otherwise, auto-join (for open rooms and restricted rooms with invitation)
           handleJoin(room.id)
         }
       })

apps/web/src/components/nav/JoinRoomModal.tsx

@@ -77,18 +77,14 @@ export function JoinRoomModal({ isOpen, onClose, onSuccess }: JoinRoomModalProps
         return
       }
 
-      if (room.accessMode === 'restricted') {
-        setError('This room is invitation-only. Please ask the host for an invitation.')
-        setIsLoading(false)
-        return
-      }
-
       if (room.accessMode === 'approval-only') {
         setNeedsApproval(true)
         setIsLoading(false)
         return
       }
 
+      // For restricted rooms, try to join - the API will check for invitation
+
       if (room.accessMode === 'password') {
         // Check if password is provided
         if (!needsPassword) {