chore: license under AGPL-3.0 and add Contributor License Agreement

- Add full AGPL-3.0 LICENSE (canonical GNU text)
- Switch README and pyproject.toml from MIT to AGPL-3.0
- Add CLA.md (individual + entity) granting relicensing rights
- Add CONTRIBUTING.md explaining workflow and why the CLA exists
- Add CLA Assistant GitHub workflow to enforce signing on PRs
- Document licensing stance in CLAUDE.md

CLA.md

@@ -0,0 +1,158 @@
+# RoboCo Contributor License Agreement
+
+Thank you for your interest in contributing to RoboCo (the "Project"),
+maintained by Renzo Franceschini (the "Maintainer").
+
+This Contributor License Agreement ("Agreement") documents the rights granted
+by contributors to the Maintainer. It applies to individual contributors; an
+entity-level version is provided in the [Entity CLA](#entity-cla) section
+below. By signing this Agreement (see [How to sign](#how-to-sign)), You accept
+and agree to its terms for Your past, present, and future Contributions to the
+Project.
+
+> **Note:** This document is provided as a starting point and has not been
+> reviewed by a lawyer. Before relying on it for a public launch, the
+> Maintainer should have it reviewed by qualified legal counsel — in
+> particular the [Governing law](#9-governing-law) section, which must be set
+> to a chosen jurisdiction.
+
+## 1. Definitions
+
+- **"You"** (or **"Your"**) means the individual or legal entity that signs
+  this Agreement.
+- **"Contribution"** means any original work of authorship, including any
+  modifications or additions to existing work, that You intentionally submit
+  to the Project in any form, including but not limited to source code, object
+  code, documentation, and configuration. It includes any Contribution You
+  have submitted prior to signing this Agreement.
+- **"Submit"** means any form of communication sent to the Project, including
+  pull requests, patches, issues, and comments, but excluding communication
+  conspicuously marked "Not a Contribution".
+- **"Maintainer"** means Renzo Franceschini **and the Maintainer's successors
+  and assigns**, including any legal entity that the Maintainer may later form
+  or transfer the Project to.
+
+## 2. Copyright license grant
+
+You retain ownership of the copyright in Your Contribution. Subject to the
+terms of this Agreement, You hereby grant to the Maintainer and to recipients
+of software distributed by the Maintainer a **perpetual, worldwide,
+non-exclusive, royalty-free, irrevocable** copyright license to reproduce,
+prepare derivative works of, publicly display, publicly perform, sublicense,
+and distribute Your Contribution and such derivative works.
+
+You further grant the Maintainer the right to **license and re-license Your
+Contribution under any license terms, including the AGPL-3.0, other
+open-source licenses, and proprietary or commercial license terms**, and to
+sublicense these rights through multiple tiers of sublicensees. You
+acknowledge that this right is what enables the Project to be offered under
+dual-licensing or commercial terms in the future.
+
+For clarity, this grant is **in addition to** — and does not limit — the
+rights You grant to the public when Your Contribution is distributed as part
+of the Project under its then-current open-source license (currently
+AGPL-3.0).
+
+## 3. Patent license grant
+
+Subject to the terms of this Agreement, You grant to the Maintainer and to
+recipients of software distributed by the Maintainer a perpetual, worldwide,
+non-exclusive, royalty-free, irrevocable (except as stated below) patent
+license to make, have made, use, offer to sell, sell, import, and otherwise
+transfer Your Contribution, where such license applies only to those patent
+claims licensable by You that are necessarily infringed by Your Contribution
+alone or by combination of Your Contribution with the Project. If any entity
+institutes patent litigation alleging that Your Contribution, or the Project
+to which You have contributed, constitutes direct or contributory patent
+infringement, then any patent licenses granted to that entity under this
+Agreement terminate.
+
+## 4. Moral rights
+
+To the fullest extent permitted by applicable law, You waive, and agree not to
+assert against the Maintainer or its licensees, any moral rights, rights of
+attribution or integrity, or similar rights You may have in Your Contribution
+that would otherwise restrict the exercise of the rights granted in Sections 2
+and 3. Where such rights cannot be waived under applicable law, You agree not
+to enforce them against the Maintainer, its licensees, or downstream
+recipients.
+
+## 5. Third-party materials
+
+If You wish to submit work that is not Your original creation, You may submit
+it to the Project separately from any Contribution, identifying the complete
+details of its source and of any license or other restriction (including
+related patents, trademarks, and license agreements) of which You are
+personally aware, and conspicuously marking the work as
+"Submitted on behalf of a third party: [named here]". Such submissions are not
+Contributions under this Agreement and are not covered by the grants above.
+
+## 6. Your representations
+
+You represent that:
+
+1. Each of Your Contributions is Your original creation, or You have
+   sufficient rights to grant the licenses in this Agreement.
+2. You are legally entitled to grant the above licenses. If Your employer has
+   rights to intellectual property You create, You represent that You have
+   received permission to make the Contributions on behalf of that employer,
+   or that Your employer has waived such rights for Your Contributions.
+3. Your Contribution does not, to Your knowledge, violate any third party's
+   copyrights, trademarks, patents, or other intellectual property rights.
+4. You will notify the Maintainer of any facts or circumstances of which You
+   become aware that would make these representations inaccurate.
+
+## 7. Disclaimer
+
+Unless required by applicable law or agreed to in writing, You provide Your
+Contributions on an "AS IS" basis, without warranties or conditions of any
+kind, either express or implied.
+
+## 8. No obligation
+
+The Maintainer is under no obligation to accept or use any Contribution. The
+decision to include a Contribution in the Project is at the Maintainer's sole
+discretion.
+
+## 9. Governing law
+
+This Agreement is governed by and construed in accordance with the laws of
+**[JURISDICTION — TO BE SET BY THE MAINTAINER, e.g. "Italy" or the relevant
+country/state]**, without regard to its conflict-of-law provisions. Any
+dispute arising out of or relating to this Agreement shall be subject to the
+exclusive jurisdiction of the courts located in that jurisdiction.
+
+> ⚠️ This placeholder MUST be set to a real jurisdiction before the CLA is
+> used in production.
+
+## 10. Entire agreement
+
+This Agreement is the entire agreement between You and the Maintainer
+concerning Your Contributions and supersedes any prior agreement on that
+subject. If any provision is held unenforceable, the remaining provisions
+remain in full force, and the unenforceable provision will be enforced to the
+maximum extent permitted by law.
+
+---
+
+## Entity CLA
+
+If You are signing on behalf of a legal entity (e.g., Your employer), the
+defined term "You" includes that entity and all entities that control, are
+controlled by, or are under common control with it. The individual signing
+represents that they are authorized to bind the entity to this Agreement. All
+other terms above apply unchanged.
+
+---
+
+## How to sign
+
+Signing is automated through the **CLA Assistant** bot:
+
+1. Open a pull request against the Project.
+2. The bot will comment on your PR with a link to this Agreement.
+3. Confirm your agreement by posting the exact comment the bot requests
+   (for example: `I have read the CLA Document and I hereby sign the CLA`).
+
+Your GitHub username and the signing timestamp are recorded so the signature
+can be verified on future contributions. This is a one-time action.