Avoid successful session-setup logging overhead

[krowvin]

Summary

Remove successful cwms_env.set_session_user_direct logging from pooled connection setup, retaining the WEB_USER check, identity/office reset, read-only reset, and unauthorized-attempt logging.

Companion CDA PR: USACE/cwms-data-api#1956. Mike's overlapping #230 removes the logging helper and changes failure reporting as well; this narrower variant remains here as the tested comparison, and can be replaced by his change after validation.

Related to USACE/cwms-data-api#1955: these measurements inform the investigation of pool sizing and isolation for short- and long-running requests.

Performance and resources

Part of an exhaustive local performance pass across CDA and Oracle. Five fresh sessions per phase, logging on/off/on, 20 setup calls per session:

Metric (mean per session)	Before: logging on	After: success logging off
Repeated setup time	7.35 ms	1.38 ms
PGA used after setup	12.14 MiB	2.62 MiB
PGA allocated after setup	12.85 MiB	2.88 MiB

Re-enabling logging returned PGA used to 11.80 MiB and repeated setup to 7.27 ms. The reported eight-second stall did not reproduce locally.

Test resource	Configuration
Database	Disposable Oracle Free 23.5 container
Physical sessions	5 per phase; 15 total
Setup calls	20 per session; 300 total
Combined CDA fixture	2 API processors, 2-GiB heap, pool maximum 30

For review: @MikeNeilson.

Validation

The fixture package compiled; 300 identity checks and 150 no-office read-only resets passed. The probe disabled only the successful log call; this patch also removes its unused message construction. Combined HTTP results and reproducible harness are in the companion CDA PR. Full database utPLSQL suite and production/RDS qualification remain outstanding.

• AI tools used

[krowvin]

Closing this as it was submitted to provide some ideas and brainstorm