chore: reconcile contribution rules and onboarding fixtures

Extract the guided setup test fixture without dropping cases. Supply current settings/discovery contracts and Opus 5.5 in the isolated Storybook boundary.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

tests/runner-e2e/installed-cli.test.ts

@@ -10,8 +10,6 @@ import { buildPaperclipServerEnvironment, buildRunnerE2EProcessEnvironment } fro
 const cells = runnerMatrix.filter(e => e.profile.id === "runner-acpx-pi");
 const roots: string[] = [];
 beforeEach(() => {
-  // pnpm's test shim can inject NODE_PATH. Installed-startup fixtures model
-  // the production launcher's clean environment, not that test shim.
   vi.stubEnv("NODE_PATH", undefined);
   vi.stubEnv("NODE_OPTIONS", undefined);
 });