perf(dashboard): lazy-load DoI tiers on Repositories page

Page now renders in ~200ms. DoI badges and KPI card show a spinner
while the background fetch resolves (~6s), then update reactively
via Observable Mutable pattern (doiData / doiLoading).

Fast path: repos, SBOM, domains, workstreams — immediate render.
Slow path: /repos/doi/summary — background, non-blocking.

Co-Authored-By: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

state-hub/dashboard/src/repos.md

@@ -7,20 +7,32 @@ import {API} from "./components/config.js";
 ```
 
 ```js
-let _repos = [], _domains = [], _sbom = [], _eps = [], _tds = [], _workstreams = [], _doi = [];
+// Fast data — page renders as soon as this resolves (~200ms)
+let _repos = [], _domains = [], _sbom = [], _eps = [], _tds = [], _workstreams = [];
 try {
-  [_repos, _domains, _sbom, _eps, _tds, _workstreams, _doi] = await Promise.all([
+  [_repos, _domains, _sbom, _eps, _tds, _workstreams] = await Promise.all([
     fetch(`${API}/repos/`).then(r => r.ok ? r.json() : []),
     fetch(`${API}/domains/`).then(r => r.ok ? r.json() : []),
     fetch(`${API}/sbom/`).then(r => r.ok ? r.json() : []),
     fetch(`${API}/extension-points/`).then(r => r.ok ? r.json() : []),
     fetch(`${API}/technical-debt/`).then(r => r.ok ? r.json() : []),
     fetch(`${API}/workstreams/`).then(r => r.ok ? r.json() : []),
-    fetch(`${API}/repos/doi/summary`).then(r => r.ok ? r.json() : []),
   ]);
 } catch {}
 ```
 
+```js
+// DoI data — lazy-loaded. Starts as [] so the page renders immediately.
+// When the fetch resolves (~6s), doiData updates and DoI badges appear.
+import {Mutable} from "observablehq:stdlib";
+const doiData = Mutable([]);
+const doiLoading = Mutable(true);
+fetch(`${API}/repos/doi/summary`)
+  .then(r => r.ok ? r.json() : [])
+  .catch(() => [])
+  .then(data => { doiData.value = data; doiLoading.value = false; });
+```
+
 ```js
 const repos       = _repos       ?? [];
 const domains     = _domains     ?? [];
@@ -28,7 +40,7 @@ const sbom        = _sbom        ?? [];
 const eps         = _eps         ?? [];
 const tds         = _tds         ?? [];
 const workstreams = _workstreams ?? [];
-const doi         = _doi         ?? [];
+const doi         = doiData;  // reactive — updates when lazy fetch completes
 
 // DoI lookups
 const doiBySlug = Object.fromEntries(doi.map(d => [d.repo_slug, d]));
@@ -121,12 +133,15 @@ const doiNoneCount     = repoRows.filter(r => r._doiTier === "none").length;
 import {withDocHelp} from "./components/doc-overlay.js";
 const _h1 = document.querySelector("#observablehq-main h1");
 if (_h1) { _h1.style.position = "relative"; withDocHelp(_h1, "/docs/repos"); }
-display(html`<p style="font-size:0.85rem;color:#6b7280;margin-top:-0.5rem;">
+display(html`<p style="font-size:0.85rem;color:#6b7280;margin-top:-0.5rem;display:flex;align-items:center;gap:0.75rem;flex-wrap:wrap;">
-  DoI tiers: <strong style="color:#ef4444;">None</strong> →
+  <span>DoI tiers: <strong style="color:#ef4444;">None</strong> →
   <strong style="color:#f97316;">Core</strong> →
   <strong style="color:#eab308;">Standard</strong> →
   <strong style="color:#22c55e;">Full</strong> —
-  <a href="/policy/repo-doi" style="color:#1d4ed8;">Definition of Integrated policy ↗</a>
+  <a href="/policy/repo-doi" style="color:#1d4ed8;">Definition of Integrated policy ↗</a></span>
+  ${doiLoading ? html`<span style="display:inline-flex;align-items:center;gap:0.35rem;color:#9ca3af;font-size:0.8rem;">
+    <span class="doi-spinner"></span> Loading DoI tiers…
+  </span>` : html`<span style="color:#16a34a;font-size:0.8rem;">✓ DoI tiers loaded</span>`}
 </p>`);
 ```
 
@@ -155,10 +170,10 @@ display(html`<div class="kpi-row">
     <p class="big-num">${gapCount}</p>
     <small>${gapCount === 0 ? "✓ All repos covered" : `⚠ ${gapCount} repo(s) not ingested`}</small>
   </div>
-  <div class="card ${doiNoneCount > 0 ? 'card-warn' : 'card-ok'}">
+  <div class="card ${doiLoading ? '' : doiNoneCount > 0 ? 'card-warn' : 'card-ok'}">
     <h3>DoI: Fully Integrated</h3>
-    <p class="big-num">${doiFullCount} / ${repoRows.length}</p>
+    <p class="big-num">${doiLoading ? html`<span class="doi-spinner" style="width:1.4rem;height:1.4rem;"></span>` : `${doiFullCount} / ${repoRows.length}`}</p>
-    <small>${doiNoneCount > 0 ? `⚠ ${doiNoneCount} at tier None` : "✓ All pass Core tier"}</small>
+    <small>${doiLoading ? "Loading…" : doiNoneCount > 0 ? `⚠ ${doiNoneCount} at tier None` : "✓ All pass Core tier"}</small>
   </div>
 </div>`);
 ```
@@ -174,6 +189,7 @@ function _sbomGap() {
 }
 
 function _doiBadge(tier) {
+  if (doiLoading) return html`<span style="color:#d1d5db;font-size:0.72rem;">…</span>`;
   const color = DOI_TIER_COLOR[tier] || "#9ca3af";
   const bg    = DOI_TIER_BG[tier]    || "#f9fafb";
   const label = DOI_TIER_LABEL[tier] || tier;
@@ -363,4 +379,12 @@ custodian register-project --domain &lt;slug&gt;</pre>
 .onboard-step strong { font-size: 0.9rem; display: block; margin-bottom: 0.3rem; }
 .onboard-step pre { background: var(--theme-background); border-radius: 4px; padding: 0.4rem 0.7rem; font-size: 0.8rem; overflow-x: auto; margin: 0 0 0.35rem; }
 .onboard-note { font-size: 0.82rem; color: var(--theme-foreground-muted, gray); margin: 0; line-height: 1.45; }
+
+.doi-spinner {
+  display: inline-block; width: 0.9rem; height: 0.9rem;
+  border: 2px solid #e5e7eb; border-top-color: #9ca3af;
+  border-radius: 50%; animation: doi-spin 0.7s linear infinite;
+  vertical-align: middle;
+}
+@keyframes doi-spin { to { transform: rotate(360deg); } }
 </style>