test(tls): add comprehensive tests for TLS package

Add complete test coverage for the TLS certificate manager package:

- Test CA certificate generation and management
- Test TLS configuration setup
- Test loading existing CA certificates
- Test certificate generation for hostnames and IPs
- Test certificate caching mechanism
- Test concurrent certificate generation
- Test PEM encoding/decoding

All tests pass successfully with proper validation of:
- Certificate properties and validity
- CA signing and verification
- Thread-safe cache operations
- IP address handling in certificates

Resolves #52

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Co-Authored-By: Claude <[email protected]>

Author: evgeniy-scherbina