WIP: Align coglet error messages with cog for integration test compatibility
Changes:
- coglet Go: Add 'predict' option not found error message matching cog
- coglet Go: Improve invalid predict format error message
- coglet Python: Update ge/le validation error messages to match cog
- Integration tests: Accept both escaped and unescaped quote formats
This is work-in-progress to make coglet pass integration tests.