fix: token extension for PWAs

web/src/app/Session.js

@@ -36,6 +36,7 @@ class Session {
     await this.db.kv.bulkPut([
       { key: "user", value: username },
       { key: "token", value: token },
+      { key: "lastExtendedAt", value: Date.now() },
     ]);
     localStorage.setItem("user", username);
     localStorage.setItem("token", token);
@@ -52,6 +53,18 @@ class Session {
     return (await this.db.kv.get({ key: "user" }))?.value;
   }
 
+  async tokenAsync() {
+    return (await this.db.kv.get({ key: "token" }))?.value;
+  }
+
+  async lastExtendedAtAsync() {
+    return (await this.db.kv.get({ key: "lastExtendedAt" }))?.value;
+  }
+
+  async setLastExtendedAtAsync() {
+    await this.db.kv.put({ key: "lastExtendedAt", value: Date.now() });
+  }
+
   exists() {
     return this.username() && this.token();
   }