refactor(admin): the console speaks the Settings vocabulary without an accent

Twenty-six of twenty-eight admin files already used the Settings card and
header. What made the console read as its own system was everything on top of
that: three hand-rolled cards, a header slot that meant five different things,
and a heading the frame took but never painted.

- `SectionFrame` drops `title` and `subtitle`. Seventeen call sites passed
  both into a component that has rendered neither since v1.18.6.1 — the shell
  reads the same keys itself. A prop contract nothing honours is a promise the
  next reader believes.
- The invite card, the four host-metric headers, and the `/admin` welcome
  card stop hand-rolling `bg-card border rounded-xl` shells with their own
  padding steps and their own heading weights. `text-sm` as a card title on
  the first card of a page, directly above a correct one, was the first thing
  the eye landed on.
- The header status slot carries status. The backups run, the invite create,
  the danger-zone wipe, and the user filters come out of it; the app-log
  refresh stays but reads as the secondary it is.
- Loading states paint their card and header. Encryption returned a bare
  spinner row and then a card, so the section jumped when the status landed —
  the fix `coach-feedback-section.tsx` already carried, applied where it was
  missing. Same for the notification-status card.
- One label/value tile. `StatusItem`, the encryption section's private `Stat`,
  the user-management inline panels and the backups upload box were four
  fills and three paddings for one role.
- The overview stopped printing the running version, build SHA and build time
  twice, thirty pixels apart. The version tile owns build identity — it is the
  one that checks for a newer release; the snapshot owns what is running.
- `ai-server-key` had three paragraphs stacked in a muted `text-xs` slot;
  one sentence stays there and the two that carry information move into the
  body as foreground. The central-codex consent copy moves the same way, and
  its disconnect is `variant="destructive"` — which `ConfirmButton` refused to
  accept, so every destructive confirm in the tree had been hand-tinting an
  outline instead.
- Leftovers: the `-mt-2` correcting the card's own rhythm, two alpha hovers on
  text, `text-[10px]` badges, the redundant `space-y-6` wrapper, the empty
  state repeating the header's CTA, and the `mt-6` a card added inside a
  frame that already spaces its children.

src/components/admin/_shared.tsx

@@ -1,6 +1,7 @@
 "use client";
 
 import { useMemo } from "react";
+import { StatTile } from "@/components/admin/_stat-tile";
 import { useQuery, useMutation, useQueryClient } from "@tanstack/react-query";
 import { toast } from "sonner";
 import { Cpu, Fingerprint, Globe, KeyRound } from "lucide-react";
@@ -149,8 +150,14 @@ export function ConfiguredBadge() {
   );
 }
 
+/**
+ * The console's label/value tile. Four hand-rolled variants of this box used
+ * to exist side by side; `StatTile` is the one, and this is the thin adapter
+ * the status grids call (the `className` they pass tints the VALUE, which is
+ * why it cannot just be `StatTile` under a different name).
+ */
 export function StatusItem({
-  icon: Icon,
+  icon,
   label,
   value,
   className,
@@ -161,13 +168,12 @@ export function StatusItem({
   className?: string;
 }) {
   return (
-    <div className="bg-muted/50 rounded-lg p-3">
-      <div className="text-muted-foreground flex items-center gap-1.5 text-xs">
-        <Icon className="h-3.5 w-3.5" />
-        {label}
-      </div>
-      <p className={`mt-1 text-sm font-semibold ${className ?? ""}`}>{value}</p>
-    </div>
+    <StatTile
+      icon={icon}
+      label={label}
+      value={value}
+      valueClassName={className}
+    />
   );
 }