Support DELETE with LIMIT and ORDER BY

[JanJakes]

Summary

Adds support for single-table DELETE statements with ORDER BY and/or LIMIT clauses, which SQLite rejects as a syntax error unless it was compiled with SQLITE_ENABLE_UPDATE_DELETE_LIMIT (not the case for standard builds, including the one bundled with WordPress Playground).

The fix mirrors the existing UPDATE LIMIT rewrite: when ORDER BY or LIMIT is present, the statement is translated to drive deletion off a rowid subquery.

-- MySQL
DELETE FROM t WHERE c = 1 ORDER BY c LIMIT 10

-- Translated SQLite
DELETE FROM `t` WHERE rowid IN (
    SELECT rowid FROM `t` WHERE `c` = 1 ORDER BY `c` ASC LIMIT 10
)

The subquery forwards tableRef, tableAlias, whereClause, orderClause, and simpleLimitClause, so queries that reference an aliased table keep the alias in scope inside the subquery (e.g. DELETE FROM t AS a WHERE a.c = 1 LIMIT 1 works).

Scope

• In scope: single-table DELETE with ORDER BY, LIMIT, or both — with or without WHERE and alias.
• Out of scope: multi-table DELETE — MySQL's grammar disallows ORDER BY/LIMIT there, so there's nothing to add.

Tests

• Translation tests covering plain LIMIT, WHERE + LIMIT, ORDER BY + LIMIT, WHERE + ORDER BY + LIMIT, and alias + WHERE + LIMIT.
• Runtime tests that insert rows, run DELETE ... LIMIT through the driver, and assert on the surviving rows — including a case that matches multiple rows to verify LIMIT is actually enforced, and an alias case.

Fixes #100