feat(storybook): wire @storybook/test-runner for story smoke tests

Every story is now executed as a smoke test (mount + no console errors)
via @storybook/test-runner. New script: pnpm test:stories runs
build-storybook then test-storybook against the static build.

Spec: §6.8

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/storybook/tsconfig.json

@@ -6,6 +6,6 @@
       "@/*": ["./src/*"]
     }
   },
-  "include": ["src/**/*.ts", "src/**/*.tsx"],
+  "include": ["src/**/*.ts", "src/**/*.tsx", "*.ts", "*.tsx"],
   "exclude": ["node_modules"]
 }