refactor: replace monolithic controller with pipeline architecture

Replace the monolithic reconcile_airflow with a five-stage pipeline:
dereference → validate → build → apply → update_status.

The build stage is infallible — all validation and fallible operations
(config generation, PodBuilder/ContainerBuilder usage, logging
validation) happen in the validate stage. Services and PDBs are now
built inline rather than delegating to service.rs and operations/.

Also updates product_logging.rs and controller_commons.rs to accept
pre-validated types (ValidatedContainerLogConfigChoice) instead of
raw Logging<C>/ContainerLogConfig, making those functions infallible.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: adwk67