if the RPC check_team_code_exists throws an exception (e.g. network error), it counts as a failed attempt->Infinite loop

### Is there an existing issue for this?

- [x] I have searched the existing issues

### What happened?

**Where**: `SupabaseService.createTeam`

**Issue**: The do-while loop tries 10 times to generate a unique ID. If the RPC check_team_code_exists throws an exception (e.g. network error), it counts as a failed attempt. 10 network errors = "Failed to create team".

**Fix**: Distinguish between "Code exists" (retry) and "Network Error" (throw immediately or retry with backoff).

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- [x] I want to work on this issue