Register Descent 3 in the product catalog

Single GameClient entry (no {res}: D3 takes -width/-height, resolution
pinned to the pod main screen; no supervisor: single process). Args boot
straight into the campaign first level for phase-0 free flight; they
change to -venue once the D3_VENUE Munga build ships. LC/MR keys
...971/...972 reserved. Catalog diff tests updated (21 passing).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Console/RedPlanet/Apps.xml

@@ -121,6 +121,27 @@
             hostType="None" />
   </Product>
 
+  <!-- Descent 3 (open-source engine + site-owned GOG assets; C:\VWE\Descent3
+       repo, venue\pack-dist.ps1 builds the package). Pod input arrives through
+       the RIOJoy "Descent 3" profile (RioGamepad HID), merged by the package's
+       postinstall. No {res} token: D3 takes -width/-height, not " -res W H" -
+       resolution is pinned to the pod main screen. Single process, no
+       supervisor; kill = terminate Descent3.exe. The args boot straight into
+       the campaign's first level (phase-0 free flight); when the D3_VENUE
+       Munga build lands, args change to "-venue -nointro{res} -framecap 60"
+       and LC/MR role entries get added (keys ...971/...972 reserved). -->
+  <Product id="B7E6D3A0-52C4-4F19-9A8E-6D40C1F2A970"
+           name="Descent 3"
+           menuText="Descent 3..."
+           hostTypeDialog="false">
+    <Launch key="B7E6D3A0-52C4-4F19-9A8E-6D40C1F2A970"
+            displayName="Descent 3"
+            exe="C:\Games\Descent3\Descent3.exe"
+            args="-pilot pod -nointro -nooutragelogo -fullscreen -width 800 -height 600 -framecap 60 -mission d3 -loadlevel 1"
+            autoRestart="true"
+            hostType="None" />
+  </Product>
+
   <!-- TeslaRel410 - the DOSBox-X preservation pods (C:\VWE\TeslaRel410 repo).
        The package (emulator\dist\TeslaPod410.zip, built by deploy\package.ps1)
        extracts to C:\Games (postinstall.bat + TeslaPod410\); pod-launch.exe is