Add SHA-3 hash reporting and Excel export

[Shreshth3]

Fixes #2

/claim #2

Summary:

• Adds SHA-3 (Keccak-256) calculation with CryptoJS.SHA3.
• Shows SHA-3 in the hash table and includes it in CSV, Excel, PDF, Word, and email forensic reports.
• Logs SHA-3 completion in the browser System Console.

Verification:

• git diff --check
• inline script parse check with Node
• loaded crypto-js from CDN and checked SHA-3 for abc
• checked CDN availability for SheetJS and jsPDF

Note: Browser UI testing was blocked by the local browser security policy in this environment, so I used static and library checks instead.