homepage: capability equivalence on the AI cards

Every fleet model card (and the #models docs section) now states, in
plain family-facing terms, what the model is equivalent to:
frank-large ~ Claude Sonnet 5 / OpenAI-Luna, frank-primary ~ Claude
Opus 4.8 / OpenAI-Terra (both Summer 2026 frontier), frank-secondary ~
last year (2025) frontier. Rendered as a new details.equiv line
(desc-equiv, styled in the head color, bare-mode clean); pinned in
homepage_config.bats.

shared/homepage/app.js

@@ -35,9 +35,10 @@ function esc(s) {
 // them (the LLM cards), else the plain description string.
 function descHTML(svc) {
     const d = svc.details;
-    if (d && (d.role || d.spec || d.inputs || d.use)) {
+    if (d && (d.role || d.spec || d.inputs || d.use || d.equiv)) {
         const lines = [];
         if (d.role) lines.push('<div class="desc-role">' + esc(d.role) + '</div>');
+        if (d.equiv) lines.push('<div class="desc-equiv">' + esc(d.equiv) + '</div>');
         if (d.spec) lines.push('<div class="desc-spec">' + esc(d.spec) + '</div>');
         if (d.inputs && d.inputs.length) lines.push('<div class="desc-inputs">Inputs: ' + esc(d.inputs.join(' · ')) + '</div>');
         if (d.use) lines.push('<div class="desc-use">Use: ' + esc(d.use) + '</div>');