dashboard: move Decision Health card into TOC sidebar column

Inject the KPI box into #observablehq-toc (the framework's right-column
aside) instead of position:fixed. The TOC column already doesn't scroll,
so no CSS tricks are needed. Falls back to a float:right inline block if
the TOC element is absent.

- Remove .kpi-sidebar-outer and its fixed positioning
- Remove min-width/max-width from .kpi-infobox; add margin-bottom to
  separate it from the TOC links below

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

dashboard/src/decisions.md

@@ -150,8 +150,10 @@ const _kpiBox = html`<div class="kpi-infobox">
 
 withDocHelp(_kpiBox, "/docs/decisions-kpi");
 
-// ── Fixed sidebar — stays in viewport top-right corner while scrolling ──────
+// ── Inject into the TOC sidebar (right column, non-scrolling) ───────────────
-display(html`<div class="kpi-sidebar-outer">${_kpiBox}</div>`);
+const _toc = document.querySelector("#observablehq-toc");
+if (_toc) _toc.prepend(_kpiBox);
+else display(html`<div style="float:right;width:215px;margin-left:1rem">${_kpiBox}</div>`);
 ```
 
 ```js
@@ -353,15 +355,6 @@ if (escalated.length > 0) {
 ```
 
 <style>
-/* ── Fixed KPI sidebar ────────────────────────────────────────────────────── */
-.kpi-sidebar-outer {
-  position: fixed;
-  top: 3.75rem;
-  right: 1.5rem;
-  width: 215px;
-  z-index: 500;
-}
-
 /* ── Live indicator ───────────────────────────────────────────────────────── */
 .live-indicator {
   font-size: 0.8rem;
@@ -376,11 +369,9 @@ if (escalated.length > 0) {
   border: 1px solid var(--theme-foreground-faint, #e0e0e0);
   border-radius: 10px;
   padding: 0.75rem 1rem;
-  min-width: 195px;
-  max-width: 240px;
   position: relative;
   box-shadow: 0 1px 6px rgba(0,0,0,0.07);
-  flex-shrink: 0;
+  margin-bottom: 1.25rem;
 }
 .kpi-infobox-title {
   font-size: 0.68rem;