sqlite: reject reentry into a running statement - #65106

Fixes: #65102

SQLite forbids stepping, resetting, or finalizing a statement while that statement's own user-defined function callback is on the stack. The callback depth added in 5cef767 (#64743) is tracked per database, so it cannot distinguish reentry into the running statement from the common pattern of querying a different statement from a callback.

This adds a per-statement flag, set for the duration of an execution, and rejects step/reset/finalize on that statement with ERR_INVALID_STATE: statement is currently being executed. Before this change:

// silently consumed rows from the iteration in progress
let iter;
db.function('reenter', () => { iter.next(); return 0; });
iter = db.prepare('SELECT reenter() FROM t').iterate();
iter.next();

// failed with "Maximum call stack size exceeded" rather than reporting the constraint
let stmt;
db.function('x', () => stmt.get());
stmt = db.prepare('SELECT x()');
stmt.get();

Covered entry points: all(), get(), run(), iterate(), iterator.next(), iterator.return(), close(), [Symbol.dispose](), and the four SQL tag store methods. close() and [Symbol.dispose]() are included because finalizing mid-step frees the virtual machine that sqlite3_step() is still executing.

Statements other than the running one are unaffected, so the lookup pattern and nested iteration over a different statement keep working — both are covered by tests.

The flag is set before parameter binding, since a getter on a named-parameters object can also reenter.

Prior art: #63183 took this approach alongside its own database-level guard. That PR was closed once #64743 landed, so this salvages the per-statement half and builds on the guard already in main.

Verified locally on macOS arm64: the new test file plus all 20 parallel/test-sqlite* tests pass, including the existing test-sqlite-udf-close.js.

Assisted-by: claude:opus-5