feat: centralize routes and navigation guards

src/presentation/routes/navigation-policy.js

@@ -0,0 +1,37 @@
+import { getRoute } from "../../contracts/routes.js";
+
+/**
+ * @param {string} routeId
+ * @param {import("../../application/ports/auth-session-port.js").SessionState} sessionState
+ */
+export function decideRouteAccess(routeId, sessionState) {
+  const route = getRoute(routeId);
+  if (route.access === "public") return { allowed: true, action: "none" };
+  if (sessionState === "authenticated") {
+    return { allowed: true, action: "none" };
+  }
+  if (sessionState === "recovery-pending") {
+    return { allowed: false, action: "wait-for-session" };
+  }
+  return { allowed: false, action: "show-sign-in" };
+}
+
+export function createRedirectLoopGuard() {
+  const visitedPairs = new Set();
+
+  return Object.freeze({
+    /**
+     * @param {string} source
+     * @param {string} target
+     */
+    allow(source, target) {
+      const pair = `${source}->${target}`;
+      if (source === target || visitedPairs.has(pair)) return false;
+      visitedPairs.add(pair);
+      return true;
+    },
+    reset() {
+      visitedPairs.clear();
+    },
+  });
+}