Remove backwards compatibility for API responses

- Clean up all backward compatibility checks for old API format
- All endpoints now consistently return { success: true, data: [...] }
- Simplify response handling across all components and pages

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

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

app/streams/page.tsx

@@ -40,9 +40,8 @@ export default function AddStream() {
       const teamsData = await teamsResponse.json();
       const streamsData = await streamsResponse.json();
 
-      // Handle both old and new API response formats
-      const teams = teamsData.success ? teamsData.data : teamsData;
-      const streams = streamsData.success ? streamsData.data : streamsData;
+      const teams = teamsData.data;
+      const streams = streamsData.data;
 
       // Map the API data to the format required by the Dropdown
       setTeams(