Fix RAND() implementation and add plugin compatibility layer

[wp-fuse]

Fix RAND() implementation and add plugin compatibility layer

Summary

This PR fixes bugs in the RAND() implementation and adds a new plugin compatibility integration (following the existing integrations/query-monitor/ pattern) to handle third-party plugin queries that are incompatible with SQLite.

Changes

RAND() fixes (wp-includes/sqlite-ast/class-wp-pdo-mysql-on-sqlite.php)

• Translate parameter-less RAND() natively to (ABS(RANDOM()) / 9223372036854775808.0) for better performance (avoids PHP UDF overhead per row).
• Seeded RAND(N) calls correctly fall through to the PHP UDF via translate_sequence(), fixing a TypeError where the function returned no value.

UDF fix (wp-includes/sqlite/class-wp-sqlite-pdo-user-defined-functions.php)

• Updated rand() to accept an optional $seed parameter and return a float (0.0–1.0) instead of an int, matching MySQL behavior.

Plugin compatibility layer (integrations/plugin-compatibility/)

New integration module (same pattern as integrations/query-monitor/) that sanitizes third-party plugin queries before they reach the AST parser:

• Locking clauses: Strips FOR UPDATE, SKIP LOCKED, and NOWAIT globally (including inside subqueries), since SQLite doesn't support row-level locking.
• Action Scheduler: Rewrites UPDATE ... JOIN syntax to UPDATE ... WHERE IN (...), escapes the unquoted group keyword, and fixes missing INTO in INSERT statements.

Test updates (tests/WP_SQLite_Driver_Tests.php)

• Updated column metadata expectations for RAND() to reflect the correct DOUBLE return type.

Boot integration (wp-includes/sqlite/db.php)

• Added require_once for the new plugin compatibility boot file.

Testing

• All 795 unit tests pass locally.
• Verified Action Scheduler claim execution works correctly in production with FluentForm.