Translation support

Prerequisites for initial translations:

• Engine support:
  • Translation support for yaml-defined strings. [#3929 #18959] [#18965]
  • Translation support for code-defined strings. [#18965]
  • Translation support for Lua-defined strings. [#18965]
  • Change server messages to send a string ID and arguments to translate client-side. [#19847]
• Tooling:
  • Automated chrome string extraction. [#5152 #18959 #20594] [#21134]
  • Automated format string sanity checks (verify that strings with formatting parameters define the same number across all translations). [#19847]
  • Utility command for showing missing translation strings. [#19847 #21490 #21525]
• Extract hardcoded strings from C# code into English translation. [#20048 #20142 #20380 #20262 #20876]
• Extract hardcoded strings from Lua code into English translation. [#20265 #20387 #20390]
• Extract yaml strings into English translation. [#20393 #20400 #20585 #20725 #21204 #21241 #21385 #21386 #21484 #21489 #21526]
• Include language setting in crash logs. #20391

Later improvements:

• Support for detecting/downloading/installing foreign content bundles (sound/art). Related to the ongoing mod browser / installation work. [#11375 and followups]
• Support for switching art/sounds based on translation.
• Per language font initialisation [#17794]

The issue is a broad translation-support checklist rather than a scoped task, and it names no files, tests, or entry points. Start by selecting one unchecked improvement and reviewing the linked issue where available, such as #17794 for per-language font initialisation. Done would require a separately defined scope and acceptance criteria for that improvement.