docs: Turkish localization, and UI enhancements

• Configured native i18n support in astro.config.mjs to support the Turkish (tr) locale.(and i will add the other languages with AI, someone can control and approve it)
• Translated the landing page, general guides, and 20+ troubleshooting documents into Turkish to make MTA help resources more accessible to the Turkish community.
• Fixed relative component import paths across translated MDX files to ensure the build compiles successfully.
• Adjusted colors to be consistent and compatible with the style of the MTA Forum and other official sites.
• Customized and updated the style of the copy-to-clipboard button.
• Refined the custom styling for callout/alert boxes (tips, errors, cautions, notes).
• Modified the left sidebar navigation behavior so that expanding one category automatically collapses the others (accordion style).