🔒 Fix Insecure Randomness for Cryptographic Salt in App.tsx

[jason420247]

🎯 What: Replace Math.random() with crypto.getRandomValues() for generating cryptographic salt vectors in TrinityKeystore.

⚠️ Risk: Math.random() is PRNG-based and predictable, which makes cryptographic salt vectors vulnerable to brute-force or prediction attacks.

🛡️ Solution: Use Web Crypto API (crypto.getRandomValues()) with cross-environment resolution (supporting window.crypto, globalThis.crypto, and Node.js environments) to produce cryptographically secure random values for cryptographic salts.

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PR created automatically by Jules for task 11034337597425991297 started by @jason420247

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