docs: a disclaimer of warranty, liability, indemnity and harmful use (#3882)

Claude-Session: https://claude.ai/code/session_013Bhtfdu3WDoF5dQjzzdcbq

Co-authored-by: jyviko <2501648+jyviko@users.noreply.github.com>
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

DISCLAIMER.md

@@ -0,0 +1,44 @@
+# Disclaimer
+
+This disclaimer covers the software, models, data, documentation and every other file in this
+repository and in the releases built from it (together, "the files").
+
+## No warranty
+
+The files are provided "as is", without warranty of any kind, express or implied, including
+warranties of accuracy, merchantability, fitness for a particular purpose and non-infringement.
+Results produced with the files, such as geometry, meshes, analyses and simulations, can be
+wrong. A qualified person must check them before anyone relies on them for a design,
+manufacturing or safety decision.
+
+## No liability
+
+To the fullest extent permitted by law, Tangency Labs and the contributors are not liable for any
+claim, damage, loss or other liability arising from the files or from their use, modification or
+distribution, whether in contract, tort or otherwise.
+
+## No indemnity
+
+Neither Tangency Labs nor any contributor indemnifies, defends or holds harmless anyone who uses,
+modifies or distributes the files, including against claims that the files infringe someone
+else's rights.
+
+## Harmful or unlawful use
+
+Tangency Labs and the contributors do not authorise, endorse or accept any responsibility for use
+of the files to harm people, animals, property or the environment, or for any unlawful use.
+Whoever uses the files is solely responsible for how they use them, for what they make with them
+and for complying with the laws that apply to them. Tangency Labs and the contributors must not be
+named or held out as responsible for any such use.
+
+## No endorsement
+
+Using, modifying or distributing the files does not mean that Tangency Labs or any contributor
+endorses you, your product or your results. Do not use the name of Tangency Labs or of a
+contributor to suggest such an endorsement without written permission.
+
+## Relation to the licence
+
+This disclaimer adds to the warranty and liability terms of the licence the files are distributed
+under. It does not restrict any right that licence grants; where the two differ, the licence
+governs.

README.md

@@ -121,6 +121,12 @@ the clean-room and licence rules, and where help is wanted most. Open work is in
 SolidCraft's continuous integration runs on [Blacksmith](https://www.blacksmith.sh), which
 sponsors its CI minutes.
 
+## Disclaimer
+
+The files in this repository are provided as is, without warranty, liability or indemnity, and
+Tangency Labs and the contributors accept no responsibility for any harmful or unlawful use of
+them: read [DISCLAIMER.md](DISCLAIMER.md).
+
 ## Licence
 
 MIT OR Apache-2.0, at your option. Developed under the