🔒 Fix Insecure Randomness for Cryptographic Salt in App.tsx

[jason420247]

🎯 What: Replaced insecure Math.random() in TrinityKeystore.getVector() in App.tsx with cryptographically secure PRNG crypto.getRandomValues().

⚠️ Risk: Math.random() generates predictable values which could allow an attacker to predict cryptographic salts generated by TrinityKeystore, weakening cryptographic security.

🛡️ Solution: Used crypto.getRandomValues() with fallback resolution for window.crypto and globalThis.crypto to generate high-entropy random uint32 integers converted to base36 representation for secure salt generation.

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PR created automatically by Jules for task 15842882760821077551 started by @jason420247

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