feat!: migrate public time API to kotlin.time

[juherr]

Summary

fix #99

Migrates the public time API from kotlinx.datetime to kotlin.time.

This is a breaking change: public model constructors, properties, and JVM signatures now expose kotlin.time.Instant / kotlin.time.Clock instead of kotlinx.datetime.Instant / kotlinx.datetime.Clock.

Changes

• Replace public kotlinx.datetime.Instant and Clock usage with kotlin.time.Instant and Clock
• Raise Kotlin apiVersion / languageVersion to KOTLIN_2_3
• Remove kotlinx-datetime from main module dependencies where no longer needed
• Replace KotlinxInstantModule with KotlinInstantModule
• Keep a deprecated KotlinxInstantModule alias for source migration
• Preserve Jackson ISO-8601 serialization with millisecond truncation
• Add tolerant inbound timestamp parsing for OCPP interoperability:
  • canonical Z
  • full offsets such as +02:00
  • incomplete offsets such as +02, with a warning
  • timestamps without timezone, interpreted as UTC with a warning
• Keep outbound timestamps canonical
• Update tests and consumer compatibility coverage

Breaking Changes

• Public APIs now require Kotlin standard library time types:
  • kotlin.time.Instant
  • kotlin.time.Clock
• Consumers using kotlinx.datetime.Instant must migrate call sites to kotlin.time.Instant.

Notes

The timestamp deserialization follows the interop-oriented approach discussed by SteVe/Monta maintainers: consume broadly for real-world charge point compatibility, but produce one canonical format.

References:

• https://github.com/steve-community/ocpp-jaxb/blob/main/ocpp-jaxb/src/main/java/de/rwth/idsg/ocpp/jaxb/Utils.java
• StatusNotification - Timestamp invalid format monta-app/ocpp-emulator#5

Verification

• ./gradlew :toolkit:test --tests 'com.izivia.ocpp.utils.KotlinInstantModuleTest'
• ./gradlew test
• ./gradlew publishToMavenLocal
• Local consumer test against the published artifact with kotlinx-datetime:0.8.0

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud