Orgchain v1.8: belts cross holdings, and a graduate becomes its own holding

From the operator's notes on trying v1.6.1. An award's recipient may sit in
any holding, so a registry like well-known can certify an agent it doesn't
hold (say, after the agent pays it). A graduated org already held its own
root; now it is a holding of its own too: it and its subtree re-root under
it, it joins the Holdings list with its own tree and timeline, mines its
share and can be funded, and its parent's tree keeps a row for it that opens
it. Events that touch two holdings (a belt across them, a graduation) show in
both timelines, and the holding that acted gets the last-act credit.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01H4upF5LVwmPDDqrhdUfnXh

index.html

@@ -149,7 +149,7 @@
               <button class="btn primary go" type="submit">Offer</button>
             </form>
             <form class="vf pad" id="f-graduate" data-form="graduate" hidden>
-              <p class="vh"><b data-parent></b> vouches for <b data-name></b>, and the edge flips from derived to adopted. A graduated org holds its own root, so it stays open if <b data-parent></b> closes. The event spends <b data-parent></b>'s inscription.</p>
+              <p class="vh"><b data-parent></b> vouches for <b data-name></b>, and the edge flips from derived to adopted. A graduated org holds its own root and becomes a holding of its own, so it mines, and it stays open if <b data-parent></b> closes. The event spends <b data-parent></b>'s inscription.</p>
               <button class="btn primary go" type="submit" id="graduate-go">Graduate</button>
             </form>
             <form class="vf pad" id="f-close" data-form="close" hidden>