feat(dev): WP-33 — in-app dev switchers for scenario + role

Surface the ?scenario= and ?role= dev stand-ins as dropdowns in the existing
debug-state devtool, so a demo can flip them with a click instead of editing the
URL. scenario.ts/role.ts gain set* setters + exported valid-value lists (reused
by the panel, no duplicated source of truth); scenario becomes tab-sticky like
role so it survives navigation. Applied via location.reload() since both are
read per-request in interceptors. Extends the debug-state eslint exemption to the
ui→infrastructure rule (same devtool precedent).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

eslint.config.mjs

@@ -230,7 +230,10 @@ export default [
   // no-restricted-imports context-direction rules above (last-wins is per rule name).
   {
     files: ['src/app/**/ui/**/*.ts', 'src/app/**/layout/**/*.ts'],
-    ignores: ['**/*.stories.ts', '**/*.spec.ts'],
+    // debug-state is the sanctioned devtool (same precedent as the cross-context
+    // exemption above): its WP-33 role/scenario switchers write the infrastructure
+    // dev-mechanism helpers directly. Never a product feature — isDevMode()-gated.
+    ignores: ['**/*.stories.ts', '**/*.spec.ts', 'src/app/shared/ui/debug-state/**'],
     plugins: { '@typescript-eslint': tseslint.plugin },
     rules: {
       '@typescript-eslint/no-restricted-imports': [