[WIP] Security Agent

[Copilot]

• [x] Create security audit report for the repository
• [x] Fix CORS configuration in the bank project API
• [x] Improve input validation in the bank project API
• [x] Restrict host permissions in browser extension
• [x] Create security utility module for browser extension
• [x] Update GitHub Actions workflow security
• [x] Add secure API key handling guidelines in documentation
• [x] Update vulnerable dependencies

Fixes #1408.

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[github-actions[bot]]

This PR has not seen any action for a while! Closing for now, but it can be reopened at a later date.