feat: enable Uzbek language (#15056)

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.

app/javascript/widget/i18n/index.js

@@ -35,6 +35,7 @@ import ta from './locale/ta.json';
 import th from './locale/th.json';
 import tr from './locale/tr.json';
 import uk from './locale/uk.json';
+import uz from './locale/uz.json';
 import vi from './locale/vi.json';
 import zh_CN from './locale/zh_CN.json';
 import zh_TW from './locale/zh_TW.json';
@@ -77,6 +78,7 @@ export default {
   th,
   tr,
   uk,
+  uz,
   vi,
   zh_CN,
   zh_TW,