Core, Data: Validate equality delete field IDs

[u70b3]

Summary

This PR brings stricter equality delete field ID validation into the Java SDK, aligned with the behavior added in iceberg-rust#2723.

The validation now rejects:

• Null or empty equality field ID lists
• Duplicate equality field IDs
• Equality field IDs that do not exist in the equality delete row schema

Changes

• Centralized validation in DeleteSchemaUtil.validateEqualityFieldIds.
• Applied validation to direct Avro, Parquet, ORC equality delete writer builders.
• Applied validation to the registry-based writer path through FileWriterBuilderImpl.
• Updated the data writer factory (RegistryBasedFileWriterFactory) to validate against the equality delete row schema, not the data schema.
• Added regression coverage for projected schemas, empty IDs, duplicate IDs, and missing IDs.

Testing

• ./gradlew :iceberg-core:test --tests org.apache.iceberg.avro.TestAvroDeleteWriters --tests org.apache.iceberg.formats.TestFormatModelRegistry :iceberg-data:test --tests org.apache.iceberg.data.TestGenericFileWriterFactory :iceberg-parquet:test --tests org.apache.iceberg.parquet.TestParquetDeleteWriters :iceberg-orc:test --tests org.apache.iceberg.orc.TestOrcDeleteWriters :iceberg-core:spotlessCheck :iceberg-data:spotlessCheck :iceberg-parquet:spotlessCheck :iceberg-orc:spotlessCheck

---

AI Disclosure

• Model: GPT-5
• Platform/Tool: Codex
• Human Oversight: partially reviewed
• Prompt Summary: Fix equality delete field ID validation findings, compare with the original PR, and update the existing PR branch as a single commit.

[u70b3]

@pvary Could you please take a look? This aligns Java equality-delete field-ID validation with the merged Rust implementation: apache/iceberg-rust#2723. All CI checks and the targeted Java writer tests pass.

[pvary]

Big part of the change is not needed if we remove the deprecated classes.
I would prefer to remove them first, and see what is needed.

[u70b3]

Sounds good, thanks. If you are planning to remove the deprecated classes, I will wait for that change and then rebase and reduce this PR to the validation still needed by the remaining paths. If you do not have bandwidth to take the cleanup, I am happy to prepare it.

[pvary]

#16449 is the PR where we work on removing the deprecated classes
If you have time, please review

[u70b3]

@pvary Rebased onto latest main now that #17696 has merged. As you suggested, the changes touching the removed deprecated classes (BaseFileWriterFactory, GenericAppenderFactory) are gone — the PR is reduced to the validation still needed by the remaining paths (14 → 11 files): DeleteSchemaUtil.validateEqualityFieldIds plus call sites in FileWriterBuilderImpl, the Avro/ORC/Parquet delete-write builders, and RegistryBasedFileWriterFactory. Verified locally: new tests pass across core/data/orc/parquet and spotless is clean. Could you take another look?