[FLINK-40002][table] Fix PushFilterInCalcIntoTableSourceScanRule for metadata filter push-down

[jnh5y]

What is the purpose of the change

• Mixed physical+metadata predicates now stay as runtime Calc filters
  instead of being routed through FilterPushDownSpec, which crashed on
  compiled-plan restore when ProjectPushDownSpec narrowed the row type.
• Fix PushFilterInCalcIntoTableSourceScanRule to separate metadata-only
  predicates from physical predicates, matching PushFilterIntoTableSourceScanRule.
• Extract the duplicated classify-push logic into a shared
  classifyAndPushFilters() method in PushFilterIntoSourceScanRuleBase.
• Document the identity contract on applyMetadataFilters Javadoc.

Does this pull request potentially affect one of the following parts:

• Dependencies (does it add or upgrade a dependency): no
• The public API, i.e., is any changed class annotated with @Public(Evolving): yes (SupportsReadingMetadata — Javadoc only, no interface change)
• The serializers: no
• The runtime per-record code paths (performance sensitive): no
• Anything that affects deployment or recovery: JobManager (and its components), Checkpointing, Kubernetes/Yarn, ZooKeeper: no
• The S3 file system connector: no

Documentation

• Does this pull request introduce a new feature? no
• If yes, how is the feature documented? not applicable

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Was generative AI tooling used to co-author this PR?

• Yes (Claude Sonnet 4.6)

[flinkbot]

CI report:

• 649290b Azure: SUCCESS

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[spuru9]

Can be simplified and the initisialisation of array dropped?

Suggested change

	@Override
	public Result applyFilters(List<ResolvedExpression> filters) {
	acceptedPhysicalFilters.addAll(filters);
	return Result.of(Collections.emptyList(), filters);
	}
	@Override
	public Result applyFilters(List<ResolvedExpression> filters) {
	return Result.of(Collections.emptyList(), filters);
	}