fix(#1438): validate cache consumers by relation generations

[justinjoy]

Summary

• store relation identity/view/storage snapshots on materialization, filtered, sorted, primary, and differential cache consumers
• reject stale cache/index reuse on same-row-count mutation, permutation, COW, and replacement
• force full rebuild/reindex on generation mismatch and isolate worker-cloned snapshots
• add direct filtered/sorted/differential/worker generation regression coverage

Validation

• normal cache/arrangement regressions: 15/15 passed
• ASan/UBSan cache/arrangement regressions: 15/15 passed
• post-format focused cache suite: 10/10 passed in normal and ASan/UBSan builds
• clang-tidy, ABI/public API, threading_doc, and diff checks passed

Scope

Stacked on #1442 (which is stacked on #1440/#1435). Pinning, borrowed-storage lifetime, and deferred destruction remain owned by #1384/#1435. The unrelated existing test_io_adapter governor-symbol link failure is not changed here.