fix(amazonq): add info banner pointing to ATX (aws#8597)

## Problem


## Solution


---

- Treat all work as PUBLIC. Private `feature/x` branches will not be
squash-merged at release time.
- Your code changes must meet the guidelines in
[CONTRIBUTING.md](https://github.com/aws/aws-toolkit-vscode/blob/master/CONTRIBUTING.md#guidelines).
- License: I confirm that my contribution is made under the terms of the
Apache 2.0 license.

Co-authored-by: David Hasani <davhasan@amazon.com>
Co-authored-by: Laxman Reddy <141967714+laileni-aws@users.noreply.github.com>

Author: 3 people

packages/core/src/amazonq/webview/ui/tabs/constants.ts

@@ -51,7 +51,7 @@ export const TabTypeDataMap: Record<Exclude<TabType, 'welcome'>, TabTypeData> =
         title: 'Q - Code Transformation',
         placeholder: 'Open a new tab to chat with Q',
         welcome:
-            'Welcome to Code Transformation! **You can also run transformations from the command line. To install the tool, see the [documentation](https://docs.aws.amazon.com/amazonq/latest/qdeveloper-ug/run-CLI-transformations.html).**',
+            'Welcome to Code Transformation!\n\n> **ℹ️ AWS Transform custom now available for Java upgrades. Agentic AI that handles version upgrades, SDK migration, and more, and improves with every execution. [Learn more](https://aws.amazon.com/transform/custom/)**',
     },
     review: {
         title: 'Q - Review',