Fix selective-approval RPC params

Update edge function to call process_approval_transaction with correct parameters:
- remove p_trace_id and p_parent_span_id
- add p_approval_mode: 'selective' and p_idempotency_key: idempotencyKey
This aligns with database function signature and resolves 500 error.

X-Lovable-Edit-ID: edt-6e45b77e-1d54-4173-af1a-dcbcd886645d

supabase/functions/process-selective-approval/index.ts

@@ -207,8 +207,8 @@ const handler = async (req: Request, context: { supabase: any; user: any; span:
         p_moderator_id: user.id,
         p_submitter_id: submission.user_id,
         p_request_id: requestId,
-        p_trace_id: rootSpan.traceId,
-        p_parent_span_id: rpcSpan.spanId
+        p_approval_mode: 'selective',
+        p_idempotency_key: idempotencyKey
       }
     );