fix: native video fullscreen, window dragging, quality picker, spinner

Enable WKWebView's elementFullscreenEnabled at startup. It is off by
default in a Tauri window, which is why the native player had no
full-screen button and why right-click 'Enter Full Screen' did nothing.
With it on, WebKit's own control appears on the video and gives the real
system fullscreen player, so the app-level workaround is gone.

Restore window dragging: data-tauri-drag-region needs
core:window:allow-start-dragging, which was missing, leaving the
title-bar strip inert.

Download quality is now a resolution picker (best/2160/1440/1080/720/
480) instead of a two-way toggle; every selector still pins AAC audio
because Opus in MP4 is silent in WebKit.

Tile titles truncate to a single line so rows stay uniform, and the
player shows a spinner while the video buffers, not just while the
stream URL resolves.

src/components/Settings.tsx

@@ -3,7 +3,7 @@ import {
   checkPrereqs, importTakeoutCsv, pickLibraryFolder, pickTakeoutFile, previewTakeoutImport,
 } from "../api";
 import { APPEARANCE_MODES, type Appearance } from "../hooks/useAppearance";
-import type { ImportPreview, Prereqs, Quality } from "../types";
+import { QUALITIES, type ImportPreview, type Prereqs, type Quality } from "../types";
 import TakeoutGuide from "./TakeoutGuide";
 import {
   BTN_CHROME, BTN_PRIMARY, Dialog, HELP, LABEL, SectionHeading, Segmented, SUBPANEL,
@@ -126,22 +126,26 @@ export default function Settings({
             <section className="border-b border-slate-200 px-5 py-4 dark:border-slate-800">
               <SectionHeading>Download quality</SectionHeading>
               <p className={`mt-1.5 ${HELP}`}>
-                <b>Best</b> takes the highest resolution available, up to 4K — above 1080p
-                that means VP9 or AV1, which your Mac decodes but older ones may not, and
-                the files are several times larger. <b>Compatible</b> caps at 1080p H.264,
-                which plays anywhere. Audio is AAC either way.
+                Above 1080p YouTube only serves VP9 and AV1. Those play here, but the
+                files are several times larger and older Macs may struggle. Pick 1080p
+                for H.264, which plays anywhere. Audio is AAC at every setting.
               </p>
-              <div className="mt-2 flex items-center justify-between gap-3">
+              <label className="mt-2 grid grid-cols-[92px_1fr] items-center gap-2">
                 <span className={LABEL}>Quality</span>
-                <Segmented
+                <select
                   value={quality}
-                  onChange={onQuality}
-                  options={[
-                    { value: "best", label: "Best (4K)" },
-                    { value: "compatible", label: "Compatible" },
-                  ]}
-                />
-              </div>
+                  onChange={(e) => onQuality(e.target.value as Quality)}
+                  className="w-full rounded-lg border border-slate-300 bg-white px-2 py-1.5
+                             text-[13px] outline-none cursor-pointer
+                             dark:border-slate-700 dark:bg-slate-800"
+                >
+                  {QUALITIES.map((q) => (
+                    <option key={q.value} value={q.value}>
+                      {q.label}
+                    </option>
+                  ))}
+                </select>
+              </label>
             </section>
 
             <section className="border-b border-slate-200 px-5 py-4 dark:border-slate-800">