test: increase test coverage from 84% to 96%

[deviantintegral]

Added new test files:

• BrowserTest: Tests for Browser class (extends Creator)
• CacheStateTest: Tests for cache state getters/setters
• LogTest: Tests for Log class including version, creator, browser, pages, and entries
• Adapter/Psr7/ResponseTest: Tests for PSR-7 Response adapter
• Repository/HarFileRepositoryTest: Tests for HAR file repository operations
• Handler/DateFormatInterfaceHandlerTest: Tests for date format interface handler
• Handler/TruncatingDateTimeHandlerTest: Tests for truncating datetime handler

Enhanced existing test files:

• RequestTest: Added tests for isResponseCached(), hasPostData(), getUrl/setUrl, getQueryString, and getMethod/setMethod
• ResponseTest: Added tests for all getters/setters and serialization
• EntryTest: Added tests for all getters/setters including pageref, time, request, response, cache, timings, serverIPAddress, connection, and initiator
• HarTest: Added tests for getLog/setLog and splitLogEntries() method
• PageTest: Added tests for getId/setId, getTitle/setTitle, and getPageTimings/setPageTimings
• CacheStateTest: Added comprehensive serialization tests

Test count increased from 82 to 148 tests (66 new tests). All tests pass successfully.