Add imprint page and header nav link

Editorial prose layout with legal notice, copyright, AI training
exclusion, and analytics disclosure. Valknar / valknar@pivoine.art
as responsible person. Imprint link added to right nav (hidden
below 820 px breakpoint).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

content/imprint.md

@@ -0,0 +1,46 @@
+---
+title: Imprint
+description: Legal notice and editorial colophon for Roux, a slow-publishing fashion journal gathered in Paris.
+layout: imprint
+---
+
+## Publication
+
+**Roux**  
+roux.pivoine.art  
+A slow-publishing fashion journal — one hundred photographs at a time.
+
+---
+
+## Responsible Person
+
+**Valknar**  
+[valknar@pivoine.art](mailto:valknar@pivoine.art)
+
+Content responsibility pursuant to § 18 Abs. 2 MStV: Valknar.
+
+---
+
+## Copyright
+
+All editorial content, photographs, and design © Roux MMXXVI. All rights reserved.
+
+No part of this publication — including photographs, text, typographic compositions, or layout — may be reproduced, distributed, or transmitted in any form without prior written permission from the editorial office.
+
+---
+
+## Photography
+
+All plates published on this site are original editorial photographs. Credits are noted within each plate's metadata where applicable.
+
+---
+
+## Technical
+
+This site is built with [Hugo](https://gohugo.io) and hosted on a private server. No personal data is collected through the site itself beyond standard server access logs. Analytics are conducted via a self-hosted, privacy-respecting instance of [Umami](https://umami.is).
+
+---
+
+## AI Training
+
+The contents of this publication — photographs, editorial text, and all associated metadata — are explicitly excluded from use in training, fine-tuning, or evaluating artificial intelligence or machine learning systems of any kind, without prior written consent.