feat: install the Quest build from the website

A Quest page on the public site (/quest) installs a DorkNet .xapk from
Chrome or Edge over WebUSB, with no adb, SideQuest or scripts: pick the
.xapk, connect the headset, install. It installs the APK, copies the OBB
to its install path (skipped when an identical one is already there) and
launches the app, with progress bars and plain-language errors for an
unsupported browser, a headset held by adb/SideQuest, a disconnect and a
copy signed with a different key.

The .xapk is read from the player's own disk: the APK and OBB are stored
uncompressed, so they stream straight out of the file without loading
1.4 GB into memory, and the server never hosts game files.

Uses Tango (@yume-chan/adb 2.6.4 and friends, MIT), pinned and bundled;
the page is lazy-loaded so the rest of the site doesn't grow. Credited in
NOTICE; README, DorkNet.Quest/README.md, docs/quest.md and the packaged
README.txt point players at the page.

NOTICE

@@ -47,6 +47,11 @@ Third-party components
   text is kept alongside the sources at
   DorkNet.Quest/src/third_party/And64InlineHook/LICENSE.
 
+  The public site's Quest installer page (DorkNet.Server/site, /quest)
+  bundles Tango (@yume-chan/adb, adb-daemon-webusb, adb-credential-web,
+  android-bin, stream-extra) by Simon Chan, under the MIT License
+  (https://github.com/yume-chan/ya-webadb).
+
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 Acknowledgements