legal: add dual MIT+Apache 2.0 license, trademark policy, and CLA (#941)

- LICENSE: add trademark notice and dual-license reference to MIT file
- LICENSE-APACHE: add full Apache 2.0 license text with ZeroClaw
  trademark clause in section 6
- TRADEMARK.md: define permitted/prohibited uses of the ZeroClaw name,
  list known unauthorized forks (openagen/zeroclaw), and document
  contributor trademark protections
- CLA.md: add Contributor License Agreement granting rights under both
  MIT and Apache 2.0, with explicit patent grant and attribution
  guarantees; contributors retain copyright ownership
- NOTICE: add official repository notice, dual-license summary, and
  contributor protection statement
- README.md: add impersonation warning section with official repo link,
  replace single MIT badge with dual-license table, add trademark and
  contributor protection summary, link CLA.md from Contributing section

README.md

@@ -879,13 +879,42 @@ A heartfelt thank you to the communities and institutions that inspire and fuel
 
 We're building in the open because the best ideas come from everywhere. If you're reading this, you're part of it. Welcome. 🦀❤️
 
+## ⚠️ Official Repository & Impersonation Warning
+
+**This is the only official ZeroClaw repository:**
+> https://github.com/zeroclaw-labs/zeroclaw
+
+Any other repository, organization, domain, or package claiming to be "ZeroClaw" or implying affiliation with ZeroClaw Labs is **unauthorized and not affiliated with this project**. Known unauthorized forks will be listed in [TRADEMARK.md](TRADEMARK.md).
+
+If you encounter impersonation or trademark misuse, please [open an issue](https://github.com/zeroclaw-labs/zeroclaw/issues).
+
+---
+
 ## License
 
-MIT — see [LICENSE](LICENSE) for license terms and attribution baseline
+ZeroClaw is dual-licensed for maximum openness and contributor protection:
+
+| License | Use case |
+|---|---|
+| [MIT](LICENSE) | Open-source, research, academic, personal use |
+| [Apache 2.0](LICENSE-APACHE) | Patent protection, institutional, commercial deployment |
+
+You may choose either license. **Contributors automatically grant rights under both** — see [CLA.md](CLA.md) for the full contributor agreement.
+
+### Trademark
+
+The **ZeroClaw** name and logo are trademarks of ZeroClaw Labs. This license does not grant permission to use them to imply endorsement or affiliation. See [TRADEMARK.md](TRADEMARK.md) for permitted and prohibited uses.
+
+### Contributor Protections
+
+- You **retain copyright** of your contributions
+- **Patent grant** (Apache 2.0) shields you from patent claims by other contributors
+- Your contributions are **permanently attributed** in commit history and [NOTICE](NOTICE)
+- No trademark rights are transferred by contributing
 
 ## Contributing
 
-See [CONTRIBUTING.md](CONTRIBUTING.md). Implement a trait, submit a PR:
+See [CONTRIBUTING.md](CONTRIBUTING.md) and [CLA.md](CLA.md). Implement a trait, submit a PR:
 - CI workflow guide: [docs/ci-map.md](docs/ci-map.md)
 - New `Provider` → `src/providers/`
 - New `Channel` → `src/channels/`