Add Decisions and Workstreams reference docs with heading help wiring

- Remove residual constitution footnote from progress page header
- Create src/docs/decisions.md: types, statuses, resolution history chart,
  filter bar, card anatomy, Decision Health KPI, escalation protocol
- Create src/docs/workstreams.md: status distribution chart, filter bar,
  table columns, dependency graph, create/update patterns
- Wire withDocHelp(h1) on Decisions and Workstreams pages pointing to new docs
- Add both pages to Reference nav section in observablehq.config.js

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

dashboard/src/workstreams.md

@@ -58,6 +58,9 @@ const _liveEl = html`<div class="live-indicator">
 </div>`;
 withDocHelp(_liveEl, "/docs/live-data");
 injectTocTop("live-indicator", _liveEl);
+
+const _h1 = document.querySelector("#observablehq-main h1");
+if (_h1) { _h1.style.position = "relative"; withDocHelp(_h1, "/docs/workstreams"); }
 ```
 
 ```js