Enables Uzbek as a selectable Chatwoot language and wires the `uz`
locale into the dashboard, widget, and survey translation loaders.
## Closes
Closes https://github.com/chatwoot/chatwoot/issues/15030
## Why
Uzbek is now available in the Chatwoot Crowdin project. The widget
translation has been proofread and is 100% translated and approved.
## What changed
- Adds Uzbek to the supported language registry
- Registers the `uz` locale with the dashboard, widget, and survey i18n
loaders
## Validation
- Proofread the Uzbek widget translation in Crowdin
- Verified placeholder preservation and corrected wording where needed
- Confirmed the widget file is 100% translated and 100% approved
This draft intentionally remains blocked until the Crowdin sync adds the
generated Uzbek locale files. It should only be marked ready and merged
after that sync lands.
