fix(core): omit TCP defaults for Unix-socket SQL config

[TDannhauer]

Summary

• Stop DbServiceFactory from injecting host=localhost / port=3306 when SQL protocol=unix.
• Use phptype-aware TCP port defaults (5432 for pgsql, 3306 otherwise).
• Extend unit coverage for unix-without-socket, explicit unix host/port, and pgsql TCP defaults.

Motivation

Follow-up to #198. That change preserved protocol/socket keys, but still always set TCP host/port defaults. PDO adapters strip protocol when building the DSN, so socket-based PostgreSQL deployments still attempted localhost:3306 and failed with connection refused.

This showed up after smartmobile login for non-admin users: the modern portal resolves SQL-backed Token / PermissionService via DbServiceFactory. Admins / legacy app entry points often avoided that path.

Changes

• buildConnectionConfig(): for protocol=unix, only pass host/port when explicitly configured.
• TCP path: default port 5432 for pgsql, 3306 otherwise.
• Unit tests updated accordingly.

Test plan

• vendor/bin/phpunit -c vendor/horde/core/phpunit.xml.dist --bootstrap vendor/autoload.php vendor/horde/core/test/Unit/Factory/DbServiceFactoryTest.php
• Smartmobile login as a non-admin user on a Unix-socket PostgreSQL deployment reaches the portal without PDO localhost:3306 errors
• TCP PostgreSQL and MySQL configs still connect with expected host/port defaults