Bug Description

After upgrading from @microsoft/teams.apps v2.0.2 to v2.0.4, calls to app.send() fail with the error "app not started" even though the app has successfully started.

The root cause is a breaking change introduced in PR #387 (released in v2.0.3). The
app.name getter was changed from reading the bot's display name from tokens to reading from the manifest.name constructor option:

Before (v2.0.2) - app.ts L136-L138:

get name() {
  return this.tokens.bot?.appDisplayName;
}

After (v2.0.3+) - app.ts L175-L177:

get name() {
 return this._manifest.name?.full;
}

The send() method checks if (!this.id || !this.name) and throws "app not started", but this error message is misleading because:

1. The app is started (app.start() completed successfully)
2. The actual issue is that manifest.name was not provided in the constructor

This is a breaking change that affects any code I had using app.send() for proactive messaging.

Steps to Reproduce

1. Install @microsoft/teams.apps v2.0.3 or later
2. Create an App instance without the manifest.name option:

const app = new App({
  clientId: "...",
  clientSecret: "...",
  tenantId: "...",
});

3. Start the app and call app.send():
   await app.start(3978);
await app.send(conversationId, "Hello"); // Throws "app not started"

Expected Behavior

Either:

• The error message should indicate the actual problem (e.g., "manifest.name is required for app.send()")
• Or the SDK should fall back to this.tokens.bot?.appDisplayName for backwards compatibility

Actual Behavior

Throws Error: app not started which is misleading

Workaround: Add manifest.name to the App constructor:

const app = new App({
  clientId: "...",
  clientSecret: "...",
  tenantId: "...",
  manifest: {
    name: { short: "MyApp", full: "My Application" },
  },
});

SDK Version

2.0.4

Node.js Version

24.5.0

Additional Context

No response