🔒 Fix Insecure Randomness for Cryptographic Salt in App.tsx

[jason420247]

🎯 What: Fixed an insecure randomness vulnerability in TrinityKeystore.getVector inside App.tsx where a non-cryptographic Math.random() was being used to generate salt vectors.

⚠️ Risk: Math.random() generates predictable values that are highly vulnerable to sequence prediction and reverse-engineering, entirely undermining the cryptographic purpose of the salt vectors and leaving them open to exploitation and session/data compromise.

🛡️ Solution: Replaced Math.random() with crypto.getRandomValues() using Uint32Array. Implemented an environment-agnostic check (window.crypto or globalThis.crypto) to safely retrieve the Web Crypto API without causing a ReferenceError on window in Node.js, Server-Side Rendering (SSR), or headless testing environments. Added full security JSDoc comments to document the fix and guide future development.

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PR created automatically by Jules for task 6157585417007201749 started by @jason420247

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