ci: mcpp 2026.8.26.1 -> 2026.8.26.2

Released and indexed. Verifies this repo against the published build rather
than against a branch.

Author: Sunrisepeak

.github/workflows/ci.yml

@@ -30,7 +30,7 @@ on:
         default: ""
 env:
   MCPP_SOURCE_REF: ${{ github.event.inputs.mcpp_ref || vars.MCPP_SOURCE_REF }}
-  MCPP_VERSION: 2026.8.26.1
+  MCPP_VERSION: 2026.8.26.2
   XLINGS_VERSION: v2026.8.17.2
   XLINGS_NON_INTERACTIVE: '1'