[Feature]: Add tests for AES encrypt/decrypt helpers

[deekshithgowda85]

Title: Add tests for AES encrypt/decrypt helpers

Description
Add a small test suite verifying that the project's AES-256-GCM encrypt/decrypt helpers produce and read the expected iv:tag:ciphertext format and round-trip correctly.

Expected outcome

• Reliable unit tests for lib/crypto.ts that run in CI and confirm correct behavior.

Relevant files

• lib/crypto.ts
• __tests__/crypto.test.ts (new)

[trivikramkalagi91-commits]

i am interested in working on this issue @deekshithgowda85

[trivikramkalagi91-commits]

/assign