[PATCH] libpq: Wrap out-of-memory error messages with libpq_gettext()

Hi,

The recent patch for passwordFromFile() error handling highlighted
that many other out-of-memory error messages in libpq still aren't
wrapped with libpq_gettext().

Attached is a patch that systematically wraps the remaining bare "out
of memory" strings across libpq with libpq_gettext() to ensure consistent
translation support. This covers:
- Authentication modules (fe-auth.c, fe-auth-scram.c, fe-auth-oauth.c)
- Connection handling (fe-connect.c, fe-cancel.c)
- Protocol and secure communication (fe-protocol3.c, fe-secure-*.c)
- Other modules (fe-exec.c, fe-lobj.c, fe-gssapi-common.c)

Cheers,
Joshua