feat(oauth-client): add StaticGating and wire interactive stage into run_pipeline
Adds StaticGating struct to pipeline.rs to track static check prerequisites
needed by the interactive stage. InteractiveOptions and InteractiveDriveMode are
moved from interactive.rs to pipeline.rs as they are needed by run_pipeline.
The run_pipeline function now conditionally runs the interactive stage if
opts.interactive is Some, building a StaticGating view from static check
results and passing it to interactive::run.
Co-Authored-By: Claude Haiku 4.5 <noreply@anthropic.com>