v0.2: All videos folder, shared watched state, release-order sorting, official icon, OAuth plumbing, docs

- per-creator "All videos" folder (release order across sub-channels); sub-channel copies use
  cpost: ids and UserDataMirror keeps played/resume state in sync
- SortNameUpdater forces release-order sort names so every client lists newest first by default
- official Floatplane icon as channel image (Primary only — a channel Thumb hid video thumbnails
  in Continue Watching) and as 16:9 plugin thumbnail; one-time image replacement on upgrade
- OAuth device-flow login (FloatplaneAuthService + settings UI); needs a Floatplane client id;
  Turnstile verified domain-bound so password login inside Jellyfin is impossible
- generic install.sh (linuxserver / official image / native), thumb.png in package + manifest
- README rewritten for a general audience, doc/usage.md with screenshots, 60 tests

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

Jellyfin.Plugin.Floatplane/Jellyfin.Plugin.Floatplane.csproj

@@ -32,6 +32,8 @@
     <EmbeddedResource Include="Configuration\configPage.html" />
     <None Remove="Resources\logo.png" />
     <EmbeddedResource Include="Resources\logo.png" />
+    <None Remove="Resources\thumb.png" />
+    <EmbeddedResource Include="Resources\thumb.png" />
   </ItemGroup>
 
 </Project>