v1.8.1

Database now avoids repeating query-file lookups, and migration commands report failures through their exit code. This makes failed migrations easier to detect in scripts and deployment tools.

• 688943ce Cache resolved query-file paths.
• 6788eccf Fix code coverage.
• 4a8e3ce9 Update the locked SQLBuilder dependency to 1.1.
• edea4098 Return a nonzero exit code when database migrations fail.