~anthropic/claude-sonnet-latest → B (6:4)

B fixes a real UX/architecture bug (redirect-based auth flow replaced with in-page morphing, consistent with the app's poem JS pattern) and simplifies auth.rs by reusing the shared layout function, providing lasting design value across success/error paths. A is a solid but narrower fix (correcting href encoding to use display_path) plus a much stronger test rewrite, but the core code change is smaller in scope and the test, while thorough, is not itself product functionality.