Fix Android INSTALL_PARSE_FAILED_NO_CERTIFICATES and resolve .NET 10 regressions

- Downgrade targetSdkVersion to 35 to avoid API 36 manifest parser bugs.
- Suppress XA1006 warning and harden PatchElfPageSize.targets (fixes CS0162 unreachable code).
- Restore explicit framework targeting in CI release workflow.
- Enable extractNativeLibs workaround for .NET 10 signing.
- Add file locking to PatchElfPageSize.targets for parallel build stability.
- Fix crashes in Multiplayer and Daily Challenge components.
- Satisfy IDE0031 and IDE0055 analyzers and improve test cloning logic.

Author: google-labs-jules[bot]

build/PatchElfPageSize.targets

@@ -129,7 +129,6 @@
                 if (lockStream != null) { lockStream.Dispose(); try { System.IO.File.Delete(lockFile); } catch { } }
             }
         }
-        return true;
       ]]></Code>
     </Task>
   </UsingTask>