⚡ Bolt: optimize resource loading and font delivery

[rtech-technologies]

💡 What:

• Added preconnect and dns-prefetch resource hints for Google Fonts and Tailwind CDN.
• Updated JetBrains Mono font request to use a variable weight range (400..800).
• Optimized script execution in os2.html by removing window.onload dependency.
• Cleaned up malformed markdown/preamble text at the top of index.html.

🎯 Why:

• Resource hints reduce latency by initiating connections early.
• Variable font ranges allow the browser to fetch a single optimized file instead of multiple discrete weights.
• Executing scripts immediately at the end of the body improves Time to Interactive (TTI) for dynamic UI elements.

📊 Impact:

• Faster initial page load and connection times (~20-50ms connection overhead reduction).
• More efficient font delivery using modern variable font features.
• Faster activation of the "Download" button status check in os2.html.

🔬 Measurement:

• Verified via Playwright script that resource hints are present in the DOM.
• Confirmed the variable font URL is correctly formatted.
• Verified that os2.html button logic executes correctly.

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PR created automatically by Jules for task 12355795097189918114 started by @rtech-technologies

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