⚡ Bolt: Optimize dashboard clock performance in index.html

[babelman97]

💡 What: The optimization implemented

Optimized the dashboard clock's updateTime function in index.html.

🎯 Why: The performance problem it solves

The original implementation was reconstructing the entire clock UI using innerHTML every second and re-creating expensive Intl objects indirectly via toLocaleString calls. This led to unnecessary DOM parsing and high CPU overhead (~1.87ms per call).

📊 Impact: Expected performance improvement

• Execution speed: Reduces execution time from ~1.87ms to ~0.024ms per call (approx. 78x speedup).
• Memory/GC: Reduces garbage collection pressure by caching and reusing Intl.DateTimeFormat instances.
• DOM Stability: Uses textContent instead of innerHTML, and dirty-checks the date to avoid redundant updates.

🔬 Measurement: How to verify the improvement

Ran a Playwright benchmark (bench_index.py) that executes updateTime 1000 times in the browser environment.

• Before: ~1.87 ms/call
• After: ~0.024 ms/call

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PR created automatically by Jules for task 3150643376778805696 started by @babelman97

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