fix(core): preserve Unix socket SQL config in DbServiceFactory

[TDannhauer]

Summary

• Fix DbServiceFactory::buildConnectionConfig() dropping protocol=unix and forcing localhost:3306, which broke rampage admin pages on PostgreSQL Unix-socket deployments
• Add unit tests for the config normalization

Motivation

Opening /admin/authentication/provider/ (or any rampage route that resolves PermissionService) on an instance using PostgreSQL over a Unix socket failed with PDOException: SQLSTATE[08006] ... localhost:3306 refused. PermissionServiceFactory resolves its connection through DbServiceFactory, which rebuilt the SQL config from a key whitelist with MySQL TCP defaults instead of preserving the socket settings from conf.php.

Changes

• buildConnectionConfig() now applies the same normalization as DbAdapterFactory (hostspec -> host, drop driverconfig, default charset) and passes everything else through -- protocol/socket reach the adapter untouched, and no host/port defaults are invented
• New test: test/Unit/Factory/DbServiceFactoryTest.php

Review follow-up

Split per review: this PR now contains only the SQL topic. The OAuth repository fallback was dropped entirely (see horde/base#134 for the conclusion on that side).

Test plan

• vendor/bin/phpunit -c phpunit.xml.dist test/Unit/Factory/DbServiceFactoryTest.php
• Verified PermissionService connects with protocol=unix PostgreSQL config
• Manual: /horde/admin/authentication/provider/ renders on a PostgreSQL Unix-socket deployment

[ralflang]

Please factor out the SQL topic from the OAuth topic into separate PRs. The OAuth topic looks wrong, the SQL topic looks mostly correct.

[TDannhauer]

Done — the PR is now SQL-only. buildConnectionConfig() mirrors the normalization DbAdapterFactory already applies instead of inventing driver-specific host/port defaults. The OAuth table probe is gone; you were right that it conflated "DB unavailable" with "OAuth not configured" — conclusion on that side is in horde/base#134.