Add HostManager for host records and host tokens

controller.hosts is now a HostManager wrapping the hosts datastore, the
same way controller.users wraps the users datastore. It owns creating
hosts (moved from HostPairingManager), revoking them (moved from
ControlConnection) and signing and verifying host tokens (moved from
Controller, generateHostToken is renamed signHostToken to match
signUserToken).

UserManager gains verifyUserToken, replacing the copies of the user
token check in WsServer and routes. The WsServer copy accepted a token
without iat when the user had no tokenValidAfter; the shared check
always requires iat, which jsonwebtoken adds by default.

Follows Cooldude2606's comment on #1161.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packages/controller/src/UserManager.ts

@@ -151,11 +151,34 @@ export default class UserManager {
 	 * @returns JWT access token for the user.
 	 */
 	signUserToken(user: UserRecord): string {
-		return jwt.sign(
-			{ aud: "user", user: user.id },
-			// auth secret is never null after startup
-			Buffer.from(this._controllerConfig.get("controller.auth_secret")!, "base64")
-		);
+		return jwt.sign({ aud: "user", user: user.id }, this._authSecret);
+	}
+
+	/**
+	 * Check a user token
+	 *
+	 * @param token - User token to check.
+	 * @returns the user the token was issued to.
+	 * @throws if the token is invalid, its user does not exist or it was issued before tokenValidAfter.
+	 */
+	verifyUserToken(token: string): User {
+		const payload = jwt.verify(token, this._authSecret, { audience: "user" });
+		if (typeof payload === "string") {
+			throw new Error("unexpected JsonWebToken type");
+		}
+		const user = this.getByNameMutable(payload.user);
+		if (!user) {
+			throw new Error("invalid user");
+		}
+		if (!payload.iat || payload.iat < user.tokenValidAfter) {
+			throw new Error("invalid token");
+		}
+		return user;
+	}
+
+	private get _authSecret() {
+		// auth secret is never null after startup
+		return Buffer.from(this._controllerConfig.get("controller.auth_secret")!, "base64");
 	}
 
 	/** Clear all player stats for specific instance */