native: support measured SQL families

[chubes4]

Summary

• Supports bounded != and <> cleanup predicates for authoritative generic table snapshots, preserving schema collation and SQL NULL behavior.
• Retains the existing title lookup and legacy multisite user-snapshot compatibility work.

Verification

• Candidate: a5b28d8b850c75194363e9429782d2754a9a101c; base: 0bec3f73f5367b692f7b0ab0acfeff55a77500ff.
• Local PHP lint passed. php tests/smoke-native-table-write.php, php tests/smoke-native-transactions.php, and php tests/smoke-native-generic-query.php passed.
• Fresh paired DME1053 Lab runs: native 965 passed / 47 failures / 32 errors / 9 skipped; MySQL 1,022 passed / 0 failures / 24 errors / 7 skipped. The native prior pair was 964 passed / 48 failures / 32 errors / 9 skipped, establishing one actual native assertion improvement without relabelling any remaining result.
• Native result receipt SHA-256: 40eeaa99f5c787214c0e27f46f88d24983647b6b380d237494245f4fe142fbe6; MySQL: fd989606c3fc6d2209ca60ec841bd618c905bb711de532371680502efb979543.
• Remaining native-only gaps include identity-correlated savepoint lifecycle and plugin-table introspection work. The shared MySQL 24 errors are WP_CLI-unavailable tests.

AI Assistance

OpenAI GPT-5.6 Terra (openai/gpt-5.6-terra) via OpenCode inspected paired evidence, implemented and tested the bounded generic snapshot mutation repair, performed paired Lab verification, and updated this draft PR. No credentials, private content, or production databases were used.