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/ThemeToggle.tsx

@@ -0,0 +1,54 @@
+"use client";
+
+import { useEffect, useState } from "react";
+
+import { cn } from "@/lib/utils";
+import { MoonIcon, SunIcon } from "@/components/icons";
+
+const STORAGE_KEY = "freezmo.theme";
+
+export function useTheme() {
+  const [theme, setTheme] = useState<"light" | "dark">("light");
+
+  useEffect(() => {
+    const stored = window.localStorage.getItem(STORAGE_KEY);
+    const isDark = stored
+      ? stored === "dark"
+      : window.matchMedia("(prefers-color-scheme: dark)").matches;
+    setTheme(isDark ? "dark" : "light");
+  }, []);
+
+  const apply = (next: "light" | "dark") => {
+    setTheme(next);
+    document.documentElement.classList.toggle("dark", next === "dark");
+    try {
+      window.localStorage.setItem(STORAGE_KEY, next);
+    } catch {
+      /* private mode */
+    }
+  };
+
+  return { theme, toggle: () => apply(theme === "dark" ? "light" : "dark") };
+}
+
+export function ThemeToggle({ className }: { className?: string }) {
+  const { theme, toggle } = useTheme();
+  const dark = theme === "dark";
+
+  return (
+    <button
+      type="button"
+      onClick={toggle}
+      aria-label={dark ? "Switch to light mode" : "Switch to dark mode"}
+      title={dark ? "Light mode" : "Dark mode"}
+      className={cn(
+        "inline-flex size-9 items-center justify-center rounded-full text-[var(--text-muted)] transition hover:bg-[var(--hover)] hover:text-[var(--text)]",
+        className,
+      )}
+    >
+      <span aria-hidden>
+        {dark ? <SunIcon className="size-5" /> : <MoonIcon className="size-5" />}
+      </span>
+    </button>
+  );
+}