Support timezone-aware datetime assertions

Fixed Which Issue?

• Fixes Z - Zero-Timezone or Zulu-timezone - While Date comparison #268
• Fixes [Feature]Support timezone-aware datetime assertions #776

PR Branch
https://github.com/officialasishkumar/zerocode/tree/issue-268-date-timezone

Motivation and Context

$LOCAL.DATETIME.AFTER and $LOCAL.DATETIME.BEFORE parsed ISO datetimes into LocalDateTime, which ignored offset semantics for values such as Z or +02:00. That meant comparisons used the wall-clock value instead of comparing equivalent instants.

This change adds a shared datetime parser for assertion expected values and actual response values. It preserves plain ISO local datetime support, honors ISO offsets and Z, and adds RFC-1123 HTTP-date parsing for values such as Last-Modified.

Validation run locally:

mvn -pl core -Dtest=ZeroCodeAssertionsProcessorImplTest test -ntp

Checklist:

• 1. New Unit tests were added

  • 1.1 Covered in existing Unit tests

• 2. Integration tests were added

  • 2.1 Covered in existing Integration tests

• 3. Test names are meaningful

• 3.1 Feature manually tested and outcome is successful

• 4. PR doesn't break any of the earlier features for end users

  • 4.1 WARNING! This might break one or more earlier earlier features, hence left a comment tagging all reviewrs

• 5. PR doesn't break the HTML report features directly

  • 5.1 Yes! I've manually run it locally and seen the HTML reports are generated perfectly fine
  • 5.2 Yes! I've opened the generated HTML reports from the /target folder and they look fine

• 6. PR doesn't break any HTML report features indirectly

  • 6.1 I have not added or amended any dependencies in this PR
  • 6.2 I have double checked, the new dependency added or removed has not affected the report generation indirectly
  • 6.3 Yes! I've seen the Sample report screenshots here, and HTML report of the current PR looks simillar.

• 7. Branch build passed in CI

• 8. No 'package.*' in the imports

• 9. Relevant DOcumentation page added or updated with clear instructions and examples for the end user

  • 9.1 Not applicable. This was only a code refactor change, no functional or behaviourial changes were introduced

• 10. Http test added to http-testing-examples module(if applicable) ?

  • 10.1 Not applicable. The changes did not affect HTTP automation flow

• 11. Kafka test added to kafka-testing-examples module(if applicable) ?

  • 11.1 Not applicable. The changes did not affect Kafka automation flow