Update documentation and installers to use alpha application packages

[jerrf010]

Summary

• Add project and Student Council documentation navigation and a multi-container installer setup with CAP and Valkey.
• Use frontend and backend :alpha container images and refresh both installers' Compose SHA-256 hashes.
• Resolve conflicts with main, preserving its license attribution and alpha's package versions; refresh the npm lockfile for the declared type packages.

Validation

• Passed Bash syntax, installer asset hash verification, npm manifest/lockfile consistency, and diff whitespace checks against main.
• Dependency installation succeeded.
• Local production build did not complete. Deployment build and Docker/PowerShell installer validation remain for CI.