Refactor `supabase/functions/upload-image/index.ts` to extract Supabase client creation into a new helper function `createAuthenticatedSupabaseClient`. This improves code organization and reusability by centralizing the logic for initializing an authenticated Supabase client using JWT authentication.
Replit-Commit-Author: Agent
Replit-Commit-Session-Id: e0cbed76-4668-44f7-95b4-a456009b318d
Replit-Commit-Checkpoint-Type: intermediate_checkpoint