Add SHA-3 hashing support

[AgentGoose32]

Closes #2

/claim

Adds SHA-3 (Keccak) hashing support to the forensic hash tool.

Changes:

• Adds a SHA-3 (Keccak) column alongside MD5 and SHA-256
• Calculates SHA-3 client-side with CryptoJS SHA3 outputLength 256
• Includes SHA-3 values in hash PDF reports
• Includes SHA-3 values in Word hash reports
• Includes SHA-3 values in email CSV reports
• Includes SHA-3 in email forensic PDFs
• Updates the helper bot hash explanation to mention SHA-3

Validation:

• Parsed index.html with Python html.parser.HTMLParser
• Verified no remaining references to removed calculateSHA256
• Verified SHA-3 output paths via source inspection

Note: this repository is a static single-page app with no package/test harness.