feat(theme): add a capabilities section band

- Replace the techStack band with project-type capabilities
- Delete the TechStack component and its section type
- Give grid cards an optional status badge
- Pad --big buttons, which Rspress ships with none
- Revise the home, services and products copy

theme/components/sections/FeatureGrid.tsx

@@ -1,15 +1,38 @@
 import type { Feature } from "@rspress/core"
 import { HomeFeature } from "@rspress/core/theme-original"
-import { arr } from "./types"
+import { arr, str, type FeatureCard } from "./types"
+
+/** The badge is interpolated into markup, so it cannot carry its own markup. */
+function escapeHtml(value: string): string {
+  return value
+    .replace(/&/g, "&")
+    .replace(/</g, "&lt;")
+    .replace(/>/g, "&gt;")
+    .replace(/"/g, "&quot;")
+}
 
 /**
  * Card grid used for both the homepage advantages and the products/services
  * grids. Delegates to the stock `HomeFeature`, which already handles `span`,
  * icons and the reveal animation — it accepts a `features` prop precisely so it
  * can be driven from somewhere other than page frontmatter.
+ *
+ * A card's `badge` is folded into the front of `details` as a span, because
+ * `HomeFeature` renders `details` through `renderHtmlOrText` (which passes HTML
+ * through) and exposes no other slot. Note this makes the whole `details` string
+ * render as HTML for badged cards — frontmatter is first-party, and
+ * `renderHtmlOrText` already does this for any string containing a tag.
  */
-export function FeatureGrid({ items }: { items?: Feature[] }) {
-  const features = arr<Feature>(items)
+export function FeatureGrid({ items }: { items?: FeatureCard[] }) {
+  const features = arr<FeatureCard>(items)?.map(({ badge, ...feature }) => {
+    const label = str(badge)
+    if (!label) return feature as Feature
+    const details = str(feature.details) ?? ""
+    return {
+      ...feature,
+      details: `<span class="rp-card-badge">${escapeHtml(label)}</span>${details}`,
+    } as Feature
+  })
   if (!features) return null
   return <HomeFeature features={features} />
 }