test : added unit tests for crypto utility functions

[tmdeveloper007]

Closes #2616.

Summary of What Has Been Done: Added unit tests for src/lib/crypto.ts covering encryptToken, decryptToken, safeCompare, getExpectedSignature, and verifyGitHubSignature. ENCRYPTION_KEY is set in beforeAll and cleaned up in afterAll.

Changes Made:

• Created test/crypto.test.ts with 29 test cases
• encryptToken: produces encrypted+iv object, both non-empty hex strings, different ciphertext each time due to random IV, handles empty string and unicode
• decryptToken: correctly roundtrips encryptToken output, returns null for tampered ciphertext, invalid IV length, non-hex ciphertext, too-short ciphertext, correctly handles unicode roundtrip
• safeCompare: true for equal strings, false for different-length strings, false for same-length different strings, empty strings, unicode strings
• getExpectedSignature: prefixed with 'sha256=', 71-char output (64 hex chars), different for different bodies/secrets
• verifyGitHubSignature: true for correctly signed body, false for tampered body, wrong prefix, no sha256=, null/undefined signature, empty body

Impact it Made: Validates AES-256-GCM token encryption/decryption roundtrip. Guards GitHub webhook signature verification used across API webhook routes.

[github-actions]

GSSoC Label Checklist 🏷️

@Umbrella-io — please apply the appropriate labels before merging:

Difficulty (pick one):

• level:beginner — 20 pts
• level:intermediate — 35 pts
• level:advanced — 55 pts
• level:critical — 80 pts

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• quality:clean — ×1.2 multiplier
• quality:exceptional — ×1.5 multiplier

Validation (required to score):

• gssoc:approved — counts for points
• gssoc:invalid / gssoc:spam / gssoc:ai-slop — does not score

Type labels (type:*) are auto-detected from files and title. Review and adjust if needed.
Points formula: (difficulty × quality_multiplier) + type_bonus

[Priyanshu-byte-coder]

CI is failing on this PR. Please fix the TypeScript/test errors before we can merge. Run npm run typecheck and npm test locally to reproduce.

[tmdeveloper007]

This PR has been closed as it has been stale for more than 2 days without recent activity or merging. If this work is still relevant, please reopen a fresh PR.