Switch interval_start/interval_end from LocalDateTime to Instant across the
entire metering data stack (entity, DTOs, parser, repository, services, controllers).
This eliminates DST-related unique constraint violations that occurred when two
different wall-clock times mapped to the same epoch millis during CET/CEST transitions.
Key changes:
- MeteringData entity: intervalStart/intervalEnd now Instant
- XlsxMeteringDataParser: produces Instant via JVM timezone conversion
- MeteringDataRepository: all queries use Instant parameters
- MeteringDataService: simplified deduplicate() (Instant has no DST ambiguity)
- Added hibernate.jdbc.time_zone=UTC and test profile for in-memory H2
- Added MeteringDataUploadIntegrationTest with real H2 database
- Added DST-specific parser and service tests
- All 216 tests passing
Bernhard Müller
fb53b169a2