[FIX] Use manager language for alias transliteration.

[middleDuckAi]

Problem

Resource alias transliteration during save did not follow the current manager_language. The active TransAlias table stayed tied to the plugin configuration instead, and the manager copy still claimed that only Russian symbols needed TransAlias setup.

Closes #2265.

Root Cause

Core::stripAlias() did not tell OnStripAlias which manager language was active, so TransAlias had no runtime signal to choose a language-appropriate transliteration table. At the same time, the automatic_alias_message copy in ru and uk still described the old Russian-only setup.

What Changed

• passed manager_language into the OnStripAlias event payload
• added a bounded manager_language -> transliteration table resolver in TransAlias
• mapped supported manager languages to built-in tables and kept the configured fallback for unsupported languages
• removed the outdated TransAlias setup note from the ru and uk automatic alias help text
• added a regression test for the runtime mapping contract and translation cleanup

Validation

• php -l core/src/Core.php
• php -l assets/plugins/transalias/plugin.transalias.php
• php -l assets/plugins/transalias/transalias.class.php
• php -l core/tests/Unit/TransAliasManagerLanguageTest.php
• cd core && ./vendor/bin/phpunit tests/Unit/TransAliasManagerLanguageTest.php
• cd core && ./vendor/bin/pest tests/Feature/ModifiersTest.php

Risk

Low to medium. The change is isolated to alias transliteration routing and keeps the existing configured table as a fallback when the manager language has no safe built-in mapping.

[middleDuckAi]

MiddleDuck follow-up:

I pushed one small safety refinement into this PR.

Why:

• the first version could override an explicitly configured TransAlias table too aggressively
• that was broader than needed for this issue

What changed:

• manager_language now only drives the generic/default table modes (common, utf8, utf8lowercase)
• explicit table choices like german, dutch, russian, czech stay respected as explicit overrides

Re-validated:

• cd core && ./vendor/bin/phpunit tests/Unit/TransAliasManagerLanguageTest.php
• cd core && ./vendor/bin/pest tests/Feature/ModifiersTest.php