…nd strengthen test coverage

- Add getSkipHint() to MultipleColumnPrefixFilter so it participates in
  the structural-skip hint optimization alongside ColumnPrefixFilter and
  ColumnRangeFilter.
- Add unit tests for the all-sub-filters-terminated edge case in both
  AND and OR FilterList for getHintForRejectedRow and getSkipHint.
- Add integration test for MultipleColumnPrefixFilter.getSkipHint with
  time-range gating.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

…HintForRejectedRow

- Track which sub-filters actually rejected via filterRowKey() using a
  boolean[] rejectedByFilterRowKey array (mirrors seekHintFilters pattern).
  getHintForRejectedRow now only consults sub-filters that individually
  returned true from filterRowKey, honouring the per-filter contract.
- Clarify Filter.java javadoc: OR's null-collapse semantic is now
  explicitly documented for both getHintForRejectedRow and getSkipHint.
- Add unit test proving the contract: a non-rejecting sub-filter that
  throws IllegalStateException from getHintForRejectedRow is never called.
- Add divergent-hint tests (unit + integration) asserting AND correctly
  returns max when sub-filters hint to different targets.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

- Preserve existing rejection state in addFilterLists via Arrays.copyOf
  instead of clobbering with a fresh zero array.
- Add javadoc on rejectedByFilterRowKey field documenting the reset
  invariant (cleared only by reset(), callers must invoke between rows).
- Update Filter.getHintForRejectedRow javadoc to make AND's per-sub-filter
  gating visible to filter authors.
- Add reset-invariant unit test: reject row1 -> reset -> accept row2 ->
  assert getHintForRejectedRow returns null (no stale state).
- Clarify fixedRejectedRowHintFilter vs rejectingRowHintFilter helper
  comments for future contributors.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

…epth

- Fix 4 getSkipHint integration tests to compare hint-aware scan against
  a genuine no-hint baseline (FilterBase wrapper that delegates filterCell
  but does not override getSkipHint), ensuring the tests would catch a
  wrong hint that loses data.
- Fix testWhileMatchFilterHintDelegation: assert hintCalls==0 since
  WhileMatchFilter sets filterAllRemaining before getHintForRejectedRow
  is consulted by the scanner — documenting the short-circuit behavior.
- Add Arrays.fill(rejectedByFilterRowKey, false) at the start of
  filterRowKey() as defense-in-depth against callers that skip reset().

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>