This commit introduces a significant number of improvements to the testing suite and documentation for the agents and parsers modules.

Key changes include:
- Fixed 9 pre-existing failing unit tests in the parsers module.
- Added new unit tests to improve test coverage for `deepagent.py` and `database/utils.py`.
- Created a new `ParserTool` to integrate the agents and parsers modules.
- Added a new integration test for the `ParserTool`.
- Added a new end-to-end test to verify the agent-parser workflow.
- Updated the root README.md with overviews of the agents and parsers modules.
- Added coverage files to .gitignore.

The entire test suite is now passing.

Author: google-labs-jules[bot]