docs: add /license page + Project sidebar group across all pages

- New license.html: plain-English summary of the Keysat
  Source-Available License 1.0 (daemon) and MIT (SDKs +
  template). TL;DR table, "what you can do / can't do" lists,
  contribution-flow explainer, links to each repo's LICENSE
  file on GitHub. Anchor sections + on-this-page TOC.
- New "Project" sidebar group (Pricing + License) inserted
  above the existing Operate group on every docs page so the
  /license page is discoverable from anywhere in the docs.

operate.html

@@ -36,6 +36,11 @@
       <a href="integrate.html#api">Admin API</a>
       <a href="integrate.html#sdks">SDKs</a>
     </div>
+    <div class="group">
+      <div class="glabel">Project</div>
+      <a href="pricing.html">Pricing</a>
+      <a href="license.html">License</a>
+    </div>
     <div class="group">
       <div class="glabel">Operate</div>
       <a href="operate.html#backups" class="active">Backups</a>