⚡ Bolt: optimize asset loading and initial execution

[rtech-technologies]

• 💡 What: Added preconnect resource hints for Google Fonts and Tailwind CDN to both index.html and os2.html. In os2.html, moved the availability check script to execute immediately rather than waiting for window.onload.
• 🎯 Why: Preconnect reduces connection setup time for critical third-party assets by initiating handshakes early. Removing window.onload for scripts at the end of the body improves Time to Interactive (TTI) for specific features, as it avoids waiting for all heavy assets (like large fonts or CDNs) to finish loading.
• 📊 Impact: Reduced connection latency for external assets and faster feature activation.
• 🔬 Measurement: Verified using curl for local response metrics and Playwright for visual/functional verification.

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PR created automatically by Jules for task 10570180835162946754 started by @rtech-technologies

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