Implement trusted run and test step insertion

[bennekrouf]

What changed

• Implemented trusted run and test step insertion in the workspace screen.
• Added logic to handle trusted runs that chain through multiple flows.
• Updated the flow definition to insert a test step between scan and commit if it doesn't already exist.
• Modified the flow book to handle one-time adoptions and ensure the test step is added to existing flows.
• Enhanced the trusted module to determine the next flow for a repository based on its status and to decide whether a run may continue.

Why

• To provide a trusted run feature that automates the process of running multiple flows for a repository, ensuring that all necessary steps are completed.
• To insert a test step into existing flows to improve the quality assurance process.

How to test

• Open the workspace screen and select a repository.
• Start a trusted run from the Commit → PR tab and observe that it chains through the Commit, Review, and Release flows as expected.
• Verify that the test step is inserted into existing flows by checking the flow definition.
• Test the behavior of the trusted run when there are no more flows to execute or when a flow fails or is rejected.
• Ensure that the trusted run stops correctly when there is nothing more to do for the repository.

[bennekrouf]

Superseded by #44. This branch shares content with main but not history — #42 was squash-merged, so merging here replays a commit that already landed and conflicts across the whole diff. #44 carries only the new work, cherry-picked onto main.