[RaphaelFakhri]

Database.transaction() runs ROLLBACK whenever the wrapped function throws. If SQLite has already rolled the transaction back (for example after INSERT OR ROLLBACK or RAISE(ROLLBACK, ...)), that ROLLBACK fails with cannot rollback - no transaction is active and replaces the real error.

This change runs ROLLBACK only while db.inTransaction is true, which matches better-sqlite3. It applies to both libsql and libsql/promise.

Changes

• compat.js and promise.js: skip ROLLBACK in the transaction wrapper when no transaction is active.
• integration-tests/tests/sync.test.js and async.test.js: add a test that triggers INSERT OR ROLLBACK inside a transaction and expects SQLITE_CONSTRAINT_PRIMARYKEY. The sync test also passes against better-sqlite3 (PROVIDER=sqlite).

Testing

• Without the fix, the new test fails on test:libsql and test:async with SQLITE_ERROR: cannot rollback - no transaction is active.
• With the fix, all integration suites pass: test:sqlite 53, test:libsql 53, test:async 68, test:extensions 29, test:concurrency 4, test:connections 2.

Fixes #243