feat: add i18n support for uninstall and container scripts

[pescn]

Summary

The following scripts are not yet part of the template/language pack build system and contain hardcoded Chinese text throughout:

• src/nvidia-uninstall.sh
• src/nvidia-container-installer.sh
• src/nvidia-container-uninstall.sh

Tasks

• Add # {{LANG_PACKS}} placeholder and gettext() calls to each script
• Create lang/nvidia-uninstall/{ZH_CN,EN_US}.sh language packs
• Create lang/nvidia-container-installer/{ZH_CN,EN_US}.sh language packs
• Create lang/nvidia-container-uninstall/{ZH_CN,EN_US}.sh language packs
• Add set -eo pipefail to scripts that only use set -e
• Verify build pipeline handles the new templates correctly

Context

Identified during PR #2 code review. These scripts work correctly but cannot be used in English-only environments without manual translation.