feat(api,web): auth et first-run — bootstrap admin, login, session, gardes

- api: auth controller/service, config env
- web: App/LoginPage/ProfilePage, garde d'auth, client API, styles
- shared: types/contrats auth
- compose: variables d'environnement first-run

Refs: #14

apps/web/src/auth/routing.ts

@@ -0,0 +1,9 @@
+import type { Route } from "../router";
+
+export function isPublicRoute(route: Route): boolean {
+  return route.name === "login" || route.name === "setup";
+}
+
+export function isPrivateRoute(route: Route): boolean {
+  return !isPublicRoute(route);
+}