test(encounters): the Phase 2 surfaces against real Postgres, and end to end

Three properties here cannot be answered by a mocked client, and each has a
shape that would pass a weaker assertion while being wrong:

- filing a visit against a due checkup twice satisfies it ONCE. Phrased as
  "the second call returned 200" it proves nothing, so the assertion is that
  lastSatisfiedAt did not move — and the instant is captured once, because two
  calls milliseconds apart are two different filings and the forward-only guard
  correctly advances on the later one.
- a lab commit writes one link PER RESULT ROW. A test that asserted "there is
  a link" would pass on one link for a three-marker panel.
- the visit list's condition filter runs in SQL. With one visit in the account
  a filter and no filter return the same list, so there are always two.

The bulk arm gets per-entry tolerance over a hundred documents, one unknown id
reported as one failed row with the rest filed, and a foreign visit refusing
the whole batch before anything is written.

The e2e spec proves the incidental-linking promise once, addressing stable
data-slot attributes rather than viewport text: a visit saves with a date and
nothing else, and a document dated inside the window offers that visit,
pre-selected because there is exactly one, and files itself against it.

src/app/checkups/page.tsx

@@ -59,10 +59,10 @@ export default function CheckupsPage() {
       <PullToRefreshIndicator {...pull} />
       <Tabs value={view} onValueChange={setView}>
         <TabsList aria-label={t("checkups.viewSwitchLabel")}>
-          <TabsTrigger value="vorsorge" data-slot="checkups-tab-vorsorge">
+          <TabsTrigger value="vorsorge" data-testid="checkups-tab-vorsorge">
             {t("checkups.tabVorsorge")}
           </TabsTrigger>
-          <TabsTrigger value="visits" data-slot="checkups-tab-visits">
+          <TabsTrigger value="visits" data-testid="checkups-tab-visits">
             {t("checkups.tabVisits")}
           </TabsTrigger>
         </TabsList>