Freezmo: self-hosted notes-to-activities study app

Next.js 15 app that turns photos, PDFs, DOCX/PPTX and text into a swipeable
feed of AI-generated activities (flashcards, multiple choice, true/false,
fill-in-the-blank, matching, ordering, short answer) using the user's own
Ollama models.

Highlights:
- All AI calls run in server route handlers; the browser never talks to Ollama.
- Bring-your-own-key mode (default): the key lives only in the browser and is
  sent per-request; server, local-daemon and shared-key modes also supported.
- Client-side document extraction (pdf.js, mammoth, jszip) with scanned-PDF
  page rendering for the vision model; notes stay in their original language.
- ChatGPT-style shell: collapsible sidebar / mobile drawer, neutral token-based
  light + dark themes, folder organisation, PWA (manifest, SW, offline page).
- Strict JSON validation with zod + auto-repair, rate limiting, and request
  guards (cross-origin, body-size, API-key sanitising).
- setup.sh bootstraps deps, .env.local and a production build.

Gitignore excludes .env*, the generated pdf.js worker and local scratch files.

components/activities/MultipleChoice.tsx

@@ -0,0 +1,100 @@
+"use client";
+
+import { useEffect, useState } from "react";
+
+import type { Activity } from "@/lib/schemas";
+
+import {
+  ActivityHeader,
+  FeedbackPanel,
+  Hint,
+  OptionTile,
+  PromptCard,
+  QuestionText,
+  type ActivityComponentProps,
+} from "./shared";
+
+type MultipleChoiceActivity = Extract<Activity, { type: "multiple_choice" }>;
+
+export function MultipleChoice({
+  activity,
+  active,
+  onAnswered,
+  onNext,
+  isLast,
+}: ActivityComponentProps<MultipleChoiceActivity>) {
+  const [selected, setSelected] = useState<number | null>(null);
+  const answered = selected !== null;
+
+  const choose = (index: number) => {
+    if (answered) return;
+    setSelected(index);
+    onAnswered(index === activity.correctIndex);
+  };
+
+  useEffect(() => {
+    if (!active || answered) return;
+    const onKey = (event: KeyboardEvent) => {
+      const target = event.target as HTMLElement | null;
+      if (target && /^(INPUT|TEXTAREA)$/.test(target.tagName)) return;
+      const index = Number.parseInt(event.key, 10) - 1;
+      if (index >= 0 && index < activity.options.length) {
+        event.preventDefault();
+        choose(index);
+      }
+    };
+    window.addEventListener("keydown", onKey);
+    return () => window.removeEventListener("keydown", onKey);
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [active, answered, activity.options.length]);
+
+  const stateFor = (index: number): "idle" | "correct" | "wrong" | "dim" => {
+    if (!answered) return "idle";
+    if (index === activity.correctIndex) return "correct";
+    if (index === selected) return "wrong";
+    return "dim";
+  };
+
+  return (
+    <>
+      <ActivityHeader type="multiple_choice" topic={activity.topic} />
+      <PromptCard>
+        <QuestionText>{activity.question}</QuestionText>
+      </PromptCard>
+
+      <div className="flex flex-col gap-2.5" role="group" aria-label="Answer options">
+        {activity.options.map((option, index) => (
+          <OptionTile
+            key={option + index}
+            state={stateFor(index)}
+            disabled={answered}
+            onClick={() => choose(index)}
+            shortcut={String(index + 1)}
+          >
+            {option}
+          </OptionTile>
+        ))}
+      </div>
+
+      {!answered ? <Hint>Tip: press 1–4 on a keyboard.</Hint> : null}
+
+      {answered ? (
+        <FeedbackPanel
+          correct={selected === activity.correctIndex}
+          explanation={activity.explanation}
+          xp={activity.xp}
+          isLast={isLast}
+          onNext={onNext}
+          detail={
+            selected === activity.correctIndex ? null : (
+              <>
+                Correct answer:{" "}
+                <span className="font-bold">{activity.options[activity.correctIndex]}</span>
+              </>
+            )
+          }
+        />
+      ) : null}
+    </>
+  );
+}