Bump the contract for the new gate, and close the ways it could read as open

src/auth/gate.ts

@@ -1,16 +1,13 @@
-// The coarse gate a route or nav node declares. One home for the rule, so the router and the menu
-// can never disagree about what a visitor may reach.
+// One home for the gate rule, so the router and the menu can never disagree about what a visitor
+// may reach. README → Public pages & menu items.
 import type { User } from "../http/context.ts";
 
-// Widest first: whoever passes an earlier gate passes it without holding anything.
 const GATES = ["public", "session", "permission"] as const;
 
-// A route or nav node names exactly one of these; discovery refuses two. Omitting all three is the
-// same as `public`, which is why stating it outright makes an open gate a choice, not an oversight.
 export interface Gate {
-  permission?: string | undefined; // the Keto Permission the caller must hold, `<resource>:<action>`
-  public?: boolean | undefined; // anyone, signed in or not
-  session?: boolean | undefined; // any signed-in user, no grant to hold; anonymous is sent to /login
+  permission?: string; // the Keto Permission the caller must hold, `<resource>:<action>`
+  public?: boolean; // anyone, signed in or not
+  session?: boolean; // any signed-in user, no grant to hold; anonymous is sent to /login
 }
 
 export function allows(gate: Gate, user: User | null): boolean {
@@ -19,7 +16,6 @@ export function allows(gate: Gate, user: User | null): boolean {
   return gate.permission == null || (user?.permissions.includes(gate.permission) ?? false);
 }
 
-// Which gates a declaration sets — discovery refuses more than one, since they contradict.
 export function gatesSet(gate: Gate | null | undefined): string[] {
   if (gate == null) return [];
   return GATES.filter((name) => (name === "permission" ? gate.permission != null : gate[name] === true));