Report question: skip a broken card and tell the server

A generated matching card arrived on a phone with three identical
definitions (the generation guards now drop those), but there was no way
to get past a bad card from inside a session. The feed chrome (deck
study, review, mistakes and exam) now has the red "!" control: one tap
records the question, skips to the next card and shows an Undo toast.

- lib/question-reports.ts: the local list (freezmo.reports.v1, zod on
  read, capped 200) is the skip state — reported cards leave every
  session type, count as "not attempted" in the results instead of
  wrong, and Undo takes a report back. A deck where everything is
  reported stays studiable so it can be regenerated.
- POST /api/reports appends one JSON line per report to
  REPORTS_DIR/reports.jsonl (shared/freezmo/reports in production, the
  dev data dir in dev). Deliberately write-only: the question text is
  readable on the server (that is the point — prompt tuning) but never
  over HTTP, since the app has no auth. Best effort: offline reports stay
  local.
- The button: a red outlined rounded square with "!", the chrome's
  control size, in both feed headers (hidden on the results slide).
- config: REPORTS_DIR + RATE_LIMIT_REPORTS (20); the deploy creates the
  shared reports dir; the dev unit and AGENTS.md note the new server
  data location.
- Suites: phase-1 (append + validation + no GET), phase-2 (button, toast,
  server POST, local copy, skip counter, hidden next session, Undo, exam
  pool). SW -> freezmo-v38.

components/ReportQuestionButton.tsx

@@ -0,0 +1,44 @@
+"use client";
+
+import { haptic } from "@/lib/haptics";
+import { useI18n } from "@/lib/i18n";
+import { reportQuestion, unreportQuestion } from "@/lib/question-reports";
+import type { Activity, Deck } from "@/lib/schemas";
+import { showToast } from "@/lib/toast";
+
+/**
+ * The red "!" report control in the feed chrome: records the question, sends
+ * the operator a copy and skips past it. Undo lives in the toast.
+ */
+export function ReportQuestionButton({
+  deck,
+  activity,
+  onSkip,
+}: {
+  deck: Deck;
+  activity: Activity;
+  onSkip: () => void;
+}) {
+  const { t } = useI18n();
+
+  return (
+    <button
+      type="button"
+      onClick={() => {
+        haptic("tap");
+        reportQuestion({ deck, activity });
+        showToast({
+          message: t("feed.reported"),
+          actionLabel: t("toast.undo"),
+          onAction: () => unreportQuestion(deck.id, activity.id),
+        });
+        onSkip();
+      }}
+      aria-label={t("feed.report")}
+      title={t("feed.report")}
+      className="grid size-9 shrink-0 place-items-center rounded-xl border-2 border-rose-400/80 text-[15px] font-black leading-none text-rose-600 transition hover:bg-rose-50 dark:border-rose-400/50 dark:text-rose-300 dark:hover:bg-rose-400/10"
+    >
+      <span aria-hidden>!</span>
+    </button>
+  );
+}