Introduces first-class support for routing application traffic through a
connection pool (e.g. PgBouncer) while allowing migration clients to
bypass the pool and connect directly to the primary.

New option: `WithConnectionPool(bool)`
---------------------------------------

`postgres.New` now accepts `WithConnectionPool(bool)`, defaulting to
`true`. Pass `WithConnectionPool(false)` to explicitly disable pool
routing — the intended usage for migration clients, which must bypass
PgBouncer to avoid statement-timeout kills on long-running queries.

Host and port resolution
------------------------

When the connection pool is enabled, host and port resolution follows a
priority chain before falling back to the primary address:

  pool_host config → pool_host secret → host config → host secret
  pool_port config → pool_port secret → port config → port secret

When the connection pool is disabled, `pool_host`/`pool_port` are
ignored entirely and the chain collapses to the primary address. This
means pooler-less deployments (e.g. Caproni) work without any
configuration change.

CrunchyData projection preset
------------------------------

The CrunchyData projection preset is extended with `pgbouncer-host` and
`pgbouncer-port` Secret key mappings. When PgBouncer is enabled in a
CrunchyData cluster, those keys are present in the pguser Secret and
will be picked up automatically — no explicit Helm values required.
Deployments without a pooler fall through to the existing `host`/`port`
keys.

Pool bypass for migration clients
----------------------------------

When `WithConnectionPool(false)` is set, `maxConns` is capped at 1.
This prevents migration clients from opening a pool of direct primary
connections, which would defeat the purpose of bypassing PgBouncer.

Bumps Fairway dependency to pick up `pool_host`/`pool_port` fields on
the `PostgreSQL` proto message (runway/team#920, Fairway side).

Issue: gitlab-com/gl-infra/platform/runway/team#920

chore(deps): update registry.gitlab.com/gitlab-com/gl-infra/common-ci-tasks-images/golang-fips docker tag to v1.26.4

Merge branch 'renovate/registry.gitlab.com-gitlab-com-gl-infra-common-ci-tasks-images-golang-fips-1.x' into 'master'

chore(deps): update registry.gitlab.com/gitlab-com/gl-infra/common-ci-tasks-images/golang-fips docker tag to v1.26.4

See merge request !518

Merged-by: Matias Alvarez <malvarez@gitlab.com>
Approved-by: Matias Alvarez <malvarez@gitlab.com>
Co-authored-by: GitLab Renovate Bot <ops-contact+gl-common-ci-tasks-self-renovate@gitlab.com>

feat(postgres): Add connection pool support via `WithConnectionPool`.

See merge request !515

Merged-by: Elliot Forbes <eforbes@gitlab.com>
Approved-by: Elliot Forbes <eforbes@gitlab.com>
Reviewed-by: Florian Forster <fforster@gitlab.com>
Co-authored-by: Florian Forster <fforster@gitlab.com>