Feat: Signin a user with email and password

[Ndevu12]

Description

This PR introduces a new feature that allows users to sign in using their email and password.
Also it Implement error handling for cases where the user tries to sign in with an invalid email or password.

Changes

• Added a new endpoint POST /user/signin that handles user sign-in.
• Implemented a function to validate the user's email and password.
• If the validation is successful, the server responds with a cookie containing the user's access token.

Test Plan

• Added unit tests for the POST /user/signin endpoint in signin.test.ts.
• The tests cover the case where a user signs in with a valid email and password.
• After all tests, the database connection is closed to prevent any hanging test cases.

[gitguardian]

⚠️ GitGuardian has uncovered 5 secrets following the scan of your pull request.

Please consider investigating the findings and remediating the incidents. Failure to do so may lead to compromising the associated services or software components.

🔎 Detected hardcoded secrets in your pull request

GitGuardian id	GitGuardian status	Secret	Commit	Filename
10624400	Triggered	Generic Password	f52b228	src/test/signin.test.ts	View secret
10624401	Triggered	Generic Password	f52b228	src/test/signin.test.ts	View secret
10624402	Triggered	Generic Password	f52b228	src/test/signin.test.ts	View secret
10624403	Triggered	Generic Password	f52b228	src/test/signin.test.ts	View secret
10802115	Triggered	Generic Password	f52b228	src/test/signin.test.ts	View secret

🛠 Guidelines to remediate hardcoded secrets

1. Understand the implications of revoking this secret by investigating where it is used in your code.
2. Replace and store your secrets safely. Learn here the best practices.
3. Revoke and rotate these secrets.
4. If possible, rewrite git history. Rewriting git history is not a trivial act. You might completely break other contributing developers' workflow and you risk accidentally deleting legitimate data.

To avoid such incidents in the future consider

• following these best practices for managing and storing secrets including API keys and other credentials
• install secret detection on pre-commit to catch secret before it leaves your machine and ease remediation.

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^{🦉 GitGuardian detects secrets in your source code to help developers and security teams secure the modern development process. You are seeing this because you or someone else with access to this repository has authorized GitGuardian to scan your pull request.}

[faid-terence]

@Ndevu12 !
Please resolve the conflicts and the Jobs are failing !