Replace passlib with pwdlib for password hashing

[emma-sg]

Closes #3179
Resolves underlying issue behind #3162 and #3163

• migrate from passlib context to pwdlib PasswordHash
• replace pwd.genword() with secrets-based generator
• update dependencies to use pwdlib with argon2+bcrypt support
• preferentially use argon2, with bcrypt fallback support (updates hash on next login)

Tested locally with multiple accounts.

Testing instructions:

1. Run cluster off of main, set up multiple accounts if desired
2. Check local mongo instance, verify that all accounts' hashes start with $2b$ (bcrypt)
3. Switch to this branch, build the backend, and update the cluster
4. Log in as any desired accounts, and ensure that the login works as expected
5. Verify that the hashes for those accounts are updated to start with $argon2id$
6. While running on this branch, create a new user. Create a password for this user, and verify that the new user's hash also starts with $argon2id$.

[socket-security]

Warning

Review the following alerts detected in dependencies.

According to your organization's Security Policy, it is recommended to resolve "Warn" alerts. Learn more about Socket for GitHub.

Action	Severity	Alert  (click "▶" to expand/collapse)
Warn		Critical CVE: npm fast-xml-parser has an entity encoding bypass via regex injection in DOCTYPE entity names CVE: GHSA-m7jm-9gc2-mpf2 fast-xml-parser has an entity encoding bypass via regex injection in DOCTYPE entity names (CRITICAL) Affected versions: >= 5.0.0 < 5.3.5; >= 4.1.3 < 4.5.4 Patched version: 4.5.4 From: ? → npm/fast-xml-parser@4.5.1 ℹ Read more on: This package | This alert | What is a critical CVE? Next steps: Take a moment to review the security alert above. Review the linked package source code to understand the potential risk. Ensure the package is not malicious before proceeding. If you're unsure how to proceed, reach out to your security team or ask the Socket team for help at support@socket.dev. Suggestion: Remove or replace dependencies that include known critical CVEs. Consumers can use dependency overrides or npm audit fix --force to remove vulnerable dependencies. Mark the package as acceptable risk. To ignore this alert only in this pull request, reply with the comment @SocketSecurity ignore npm/fast-xml-parser@4.5.1. You can also ignore all packages with @SocketSecurity ignore-all. To ignore an alert for all future pull requests, use Socket's Dashboard to change the triage state of this alert.

View full report