I added `type: 'clientSecrets'` and `type: 'token'` in #387 . Looks like
ATK is using `TokenCredentials` directly which breaks since they don't
provide the value of `type` by default. In this PR, I am removing those
type fields and inferring them from the actual values.

skip-test-verification

In v2.0.3, `app.name` was changed from reading
`tokens.bot?.appDisplayName` to `manifest.name?.full`. The `send()`
method's validation check `if (!this.id || !this.name)` now throws "app
not started" when `manifest.name` is not provided, even when the app has
started successfully.

## Changes

- **Removed `!this.name` validation** in `send()` method - only
`!this.id` is required
- **Fallback to app ID for bot name** when `manifest.name` is undefined
(`name: this.name || this.id`)
- **Added tests** covering send with/without manifest.name, and proper
error when app ID is missing

## Example

```typescript
// This now works without requiring manifest.name
const app = new App({
  clientId: "...",
  clientSecret: "...",
  tenantId: "...",
  // No manifest.name needed
});

await app.start();
await app.send(conversationId, "Hello"); // ✓ Works (uses app ID as bot name)
```

The `app.name` getter is already marked `@deprecated` and should not be
used for validation.

<!-- START COPILOT CODING AGENT SUFFIX -->



<details>

<summary>Original prompt</summary>

> 
> ----
> 
> *This section details on the original issue you should resolve*
> 
> <issue_title>[Bug]: Misleading "app not started" error when
manifest.name is not configured (breaking change in
v2.0.3)</issue_title>
> <issue_description>### 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](#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](https://github.com/microsoft/teams.ts/blob/ece19d488f7975b11f702676b1c6b02e692f66e0/packages/apps/src/app.ts#L136-L138):
>   ```typescript
>   get name() {
>     return this.tokens.bot?.appDisplayName;
>   }
> ```
> 
> **After (v2.0.3+)** - [`app.ts`
L175-L177](https://github.com/microsoft/teams.ts/blob/8638fbfd3e4e253d04b2e7514ef373ef66ed9546/packages/apps/src/app.ts#L175-L177):
>    ```typescript
> get name() {
>     return this._manifest.name?.full;
>   }
> ```
> The
[send()](https://github.com/microsoft/teams.ts/blob/33c95aee06f5583083c2e456d45666fa3e43242c/packages/apps/src/app.ts#L403-L405)
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:
>   ```typescript
> 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:
>   ```typescript
> 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_</issue_description>
> 
> ## Comments on the Issue (you are @copilot in this section)
> 
> <comments>
> <comment_new><author>@heyitsaamir</author><body>
> Thanks! Yeah that is indeed a bug. We should not be looking at the
name when preparing to send. </body></comment_new>
> </comments>
> 


</details>

- Fixes #415

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Co-authored-by: copilot-swe-agent[bot] <[email protected]>
Co-authored-by: heyitsaamir <[email protected]>