Authorization denial should result in error+ready-for-query

[mostafa]

Ticket(s)

Description

BuildAccessDeniedResponse was using postgres.BuildTerminateWithError, which builds ErrorResponse + pgproto3.Terminate (type byte 'X'). The Terminate message is a frontend (client-to-server) message in the PostgreSQL wire protocol, so sending it from the server to the client during query execution causes psql/libpq to encounter an invalid backend message type and hang indefinitely.

This changes BuildAccessDeniedResponse to build ErrorResponse + ReadyForQuery instead. ReadyForQuery (type 'Z', transaction status 'I') is the correct PostgreSQL protocol response after a query error — it tells the client the server is ready for the next command and keeps the session open.

BuildAuthFailResponse (for wrong passwords) is left unchanged, since Terminate is appropriate there — the connection is being rejected during the startup/auth phase.

Related PRs

• https://github.com/gatewayd-io/gatewayd/pull/899

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• I have made corresponding changes to the documentation (docs).
• I have added tests for my changes.

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