Missing NOTICE file — Apache 2.0 §4(d) compliance

### Summary
This repository redistributes code derived from [minitap-ai/mobile-use](https://github.com/minitap-ai/mobile-use), which is Apache-2.0 licensed and ships a `NOTICE` file. Apache 2.0 **§4(d)** requires that redistributions of a derivative work retain the notices from the original's `NOTICE` file. This repo has a `LICENSE` but no `NOTICE`, so those upstream attribution notices are not being carried forward.

### Requirement
Per Apache 2.0 §4(d): if the original work includes a `NOTICE` file, redistributions must include a readable copy of the attribution notices it contains. Since `mobile-use` ships one, propagating it is mandatory, not optional.

### Upstream NOTICE contents
```
Mobile-Use
Copyright 2025-2026 Minitap, Inc.

This product includes software and architectural methodologies developed by
Minitap, Inc. (https://github.com/minitap-ai/mobile-use)

ATTRIBUTION REQUEST:
While the Apache 2.0 license only requires preserving copyright notices,
we kindly request that derivative works, redistributions, or products
inspired by the logic/architecture of this repository include a prominent
attribution to "Minitap, Inc." in the documentation and "About" sections
of the software. This is a request, not a legal requirement.
```

### Suggested fix
Add a `NOTICE` file at the repo root containing the upstream notices above (plus any Google-authored notices as appropriate). This is addressed in #76.

Check issue #76 first, since this issue says the work is addressed there. If it remains unhandled, review the upstream NOTICE text in the issue and the repository root alongside LICENSE; done means a readable root NOTICE preserves the required upstream attribution notices and any appropriate Google-authored notices.

Written by the indexing model from the issue text.