[core][python] Improve data evolution row-id conflict diagnostics

[JingsongLi]

Summary

This PR improves Data Evolution row-id range conflict detection so normal data files and dedicated storage files are checked separately. It prevents adjacent normal data files from being reported without the blob/vector file that actually connects their row-id ranges.

Changes

• Split Java row-id range conflict checks into normal data-file conflicts and dedicated blob/vector file anchor validation.
• Added matching PyPaimon logic for blob and vector dedicated files.
• Added Java and Python regression coverage for a dedicated file spanning adjacent data-file ranges.

Testing

• mvn -pl paimon-core -Pfast-build -Dtest=ConflictDetectionTest surefire:test
• PYTHONPATH=paimon-python python -m pytest paimon-python/pypaimon/tests/write/conflict_detection_test.py -q

Notes

The Java test was run with the surefire goal after locally compiling the touched classes, because the full local paimon-core test lifecycle is currently blocked by unrelated compile errors in this checkout.

[leaves12138]

Thanks for the clarification. If the goal of this PR is only to improve the diagnostics, I think this direction is reasonable.

Before merging, could we please tighten two small points so Java and PyPaimon stay aligned and the intended non-conflict cases are covered?

1. PyPaimon consistency: check_row_id_existence still special-cases only DataFileMeta.is_blob_file(...). It would be better to reuse the new _is_dedicated_file(...) helper there as well, so vector files follow the same semantics as Java's dedicatedStorageFile(...).

2. Positive regression coverage: the new negative test for a dedicated file spanning multiple data-file ranges is useful. Could we also add positive cases in both Java and Python for:

   • adjacent normal data files without a dedicated bridge should not conflict;
   • a dedicated file fully covered by one normal data-file range should not conflict.

With those covered, this looks good to merge as a diagnostics-only improvement. This PR should not be interpreted as allowing blob/vector compaction to span multiple normal data-file row-id ranges.

[JingsongLi]

Addressed the review comments in the latest push:\n\n- PyPaimon check_row_id_existence now reuses _is_dedicated_file(...), so vector files follow the same semantics as blob files.\n- Added Java and Python positive coverage for adjacent normal data files without a dedicated bridge.\n- Added Java and Python positive coverage for a dedicated file fully covered by one normal data-file range.\n\nVerified locally with:\n- mvn -pl paimon-core -DskipTests spotless:check\n- mvn -pl paimon-core -Pfast-build -Dtest=ConflictDetectionTest surefire:test after compiling the changed test class\n- PYTHONPATH=paimon-python python -m pytest paimon-python/pypaimon/tests/write/conflict_detection_test.py -q

[leaves12138]

LGTM. Reviewed the row-id conflict diagnostics changes for Java and Python, and verified with targeted ConflictDetection tests.