[platinumhamburg]

Purpose

Closes #5004.

Undo recovery currently copies every changelog row before discarding changes that cannot produce an undo. Filter scanner-backed rows before materialization to avoid unnecessary column copying on wide tables.

Brief change log

• Add internal filtered polling that copies only selected rows while preserving consumed offsets and the scanned-record poll limit.
• Select the first relevant change per primary key within each recovery poll, without prematurely updating persistent recovery deduplication.
• Preserve ordinary polling for other LogScanner implementations and keep returned row values independent of scanner buffers.

Tests

• 52 focused unit tests covering fetch buffers, filtered poll limits and offset progress, selected-row ownership, undo selection, and executor behavior.
• 5 local UndoRecoveryManagerITCase tests covering full and partial updates, partitioned tables, idempotency, and scanner failure.
• 8 local Flink120UndoRecoveryITCase tests covering checkpoint failover, producer-offset recovery, savepoint rescaling, and bounded jobs.
• Checkstyle, Spotless, and RAT checks passed during the targeted Maven build.

API and Format

Adds an @Internal method to LogScannerImpl. The LogScanner interface and storage format are unchanged.

Documentation

No user-facing configuration changes.