Initial commit — Tauri image gallery with sqlite-vec

Sets up Tauri v2 + React frontend with SQLite metadata store,
sqlite-vec for CLIP embedding infrastructure, and r2d2 connection
pool replacing the single Arc<Mutex<Connection>>. Indexer now uses
rayon for parallel file metadata collection.

src/App.tsx

@@ -0,0 +1,34 @@
+import { useEffect } from "react";
+import { useGalleryStore } from "./store";
+import { Sidebar } from "./components/Sidebar";
+import { MenuBar } from "./components/MenuBar";
+import { Toolbar } from "./components/Toolbar";
+import { Gallery } from "./components/Gallery";
+import { Lightbox } from "./components/Lightbox";
+
+export default function App() {
+  const { loadFolders, loadImages, subscribeToProgress } = useGalleryStore();
+
+  useEffect(() => {
+    loadFolders().then(() => loadImages(true));
+    let unlisten: (() => void) | undefined;
+    subscribeToProgress().then((fn) => {
+      unlisten = fn;
+    });
+    return () => {
+      unlisten?.();
+    };
+  }, []);
+
+  return (
+    <div className="flex h-screen bg-gray-950 text-white overflow-hidden select-none">
+      <Sidebar />
+      <main className="flex-1 flex flex-col min-w-0">
+        <MenuBar />
+        <Toolbar />
+        <Gallery />
+      </main>
+      <Lightbox />
+    </div>
+  );
+}