Add missing Vietnamese translations for settings.json

[hongphong214365]

Summary

This PR adds the missing Vietnamese translations in settings.json.

Translated keys include:

• accountDialogButtonTooltip
• appNavigationBarPositionLabel
• appNavigationBarPositionTop
• appNavigationBarPositionLeft
• modelDefaultsLabel
• modelLoadingGuardrails.alwaysAllowLoadAnyway
• autoDeleteExtensionPacks
• toolConfirmation
• defaultContextLength
• jitTTL

I also translated several remaining English strings inside the newly added sections to keep the Vietnamese localization consistent.

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[hongphong214365]

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[hongphong214365]

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