fix(day): head the since-last-visit card with TileHeader at the compact density

The card hand-built an uppercase h3 and ran a density of its own. It
now takes TileHeader size="sm" (which gains an h3 heading for a card
under a section that owns the h2) and the compact card rhythm.

src/components/day/since-last-visit.tsx

@@ -17,7 +17,8 @@ import {
 } from "lucide-react";
 
 import { Button } from "@/components/ui/button";
-import { Card, CardContent } from "@/components/ui/card";
+import { Card, CardContent, CardHeader } from "@/components/ui/card";
+import { TileHeader } from "@/components/insights/tile-header";
 import { QueryErrorRow } from "@/components/ui/query-error-row";
 import type { EncounterDTO } from "@/lib/encounters/dto";
 import { apiGet } from "@/lib/api/api-fetch";
@@ -35,7 +36,7 @@ import {
 import { getUnitForType } from "@/lib/measurements/unit-map";
 import { queryKeys } from "@/lib/query-keys";
 
-import { DAY_SECTION_LABEL, dayTitle, useNotableText } from "./day-sections";
+import { dayTitle, useNotableText } from "./day-sections";
 import { DayLink } from "./day-link";
 import { dateKeyOfInstant } from "./day-url";
 import { tileKeyOf } from "./day-values-model";
@@ -212,24 +213,27 @@ export function SinceLastVisit({
   const nextDay = dateKeyOfInstant(next.occurredAt, timeZone);
 
   return (
-    <Card className="gap-3 py-3 md:gap-3 md:py-4">
+    <Card className="gap-2 py-3 md:py-4">
+      <CardHeader>
+        <TileHeader
+          size="sm"
+          icon={Stethoscope}
+          id={`since-last-visit-${next.id}`}
+          titleAs="h3"
+          title={t("day.sinceLastVisit.title", { date: lastLabel })}
+          right={
+            <span className="text-muted-foreground text-xs">
+              {tCount("day.sinceLastVisit.count", rows.length)}
+            </span>
+          }
+        />
+      </CardHeader>
       <CardContent>
         <section
           data-slot="since-last-visit"
           aria-labelledby={`since-last-visit-${next.id}`}
           className="space-y-2"
         >
-          <div className="flex items-baseline justify-between gap-3">
-            <h3
-              id={`since-last-visit-${next.id}`}
-              className={DAY_SECTION_LABEL}
-            >
-              {t("day.sinceLastVisit.title", { date: lastLabel })}
-            </h3>
-            <span className="text-muted-foreground shrink-0 text-xs">
-              {tCount("day.sinceLastVisit.count", rows.length)}
-            </span>
-          </div>
           <ul className="border-border divide-border divide-y rounded-lg border px-3.5">
             {visible.map((row) => (
               <li

src/components/encounters/__tests__/visits-section.test.tsx

@@ -297,5 +297,20 @@ describe("<VisitsSection> since the last visit", () => {
     expect(html).toContain('data-slot="since-last-visit"');
     expect(html).toContain('data-slot="since-last-visit-row"');
     expect(upcomingCards(html)).toBe(upcomingCards(baseline) + 1);
+    // The card heads like every compact card: TileHeader at the small size,
+    // a real heading under the section's own, at the compact density.
+    const card = html.slice(
+      html.lastIndexOf(
+        '<div data-slot="card"',
+        html.indexOf("since-last-visit-"),
+      ),
+    );
+    expect(card).toMatch(
+      /^<div data-slot="card" class="[^"]*gap-2 py-3 md:py-4/,
+    );
+    expect(card).toContain('data-slot="tile-header"');
+    expect(card).toMatch(
+      /<h3 id="since-last-visit-[^"]+" data-slot="card-title" class="[^"]*text-sm/,
+    );
   });
 });

src/components/insights/tile-header.tsx

@@ -58,9 +58,11 @@ interface TileHeaderProps {
    * owning block (the recovery blocks) or a grid of sibling tiles (dashboard
    * tiles, insights overview grids) both nest correctly as `h1 → h2, h2, …`;
    * just don't nest a `titleAs="h2"` tile inside another heading's own
-   * subsection. Default (unset) keeps every other tile a plain CardTitle.
+   * subsection. `"h3"` is the same for a card that sits inside a section
+   * which already owns an `h2` (the since-last-visit card under the visits
+   * section). Default (unset) keeps every other tile a plain CardTitle.
    */
-  titleAs?: "h2";
+  titleAs?: "h2" | "h3";
 }
 
 export function TileHeader({
@@ -73,6 +75,7 @@ export function TileHeader({
   id,
   titleAs,
 }: TileHeaderProps) {
+  const Heading = titleAs ?? "h2";
   const titleClassNames = cn(
     size === "sm" ? "text-sm" : "text-base",
     titleClassName,
@@ -93,16 +96,16 @@ export function TileHeader({
           aria-hidden="true"
         />
       ) : null}
-      {titleAs === "h2" ? (
+      {titleAs ? (
         // Heading semantics with the exact CardTitle visual treatment so the
-        // tile can carry a real `<h2>` where it owns the subpage's heading.
-        <h2
+        // tile can carry a real heading where it owns one.
+        <Heading
           id={id}
           data-slot="card-title"
           className={cn("leading-none font-semibold", titleClassNames)}
         >
           {title}
-        </h2>
+        </Heading>
       ) : (
         <CardTitle id={id} className={titleClassNames}>
           {title}