ci: validate every member with mcpp 2026.9.30.1; latest_mcpp -> 2026.9.30.1 (#492)

mcpp 2026.9.30.1 (mcpp-community/mcpp#743) is released and indexed (openxlings/xim-pkgindex#912). The full sweep with it (run 36651996579) passed: 28 jobs succeeded and 1 was skipped. min_mcpp is unchanged.

Author: Sunrisepeak

.github/workflows/validate.yml

@@ -407,7 +407,12 @@ env:
   # across selections and runs after those of the members it depends on, the
   # build database plans by configuration, and a build reports each step once
   # with its outcome while a status line states the build.
-  MCPP_VERSION: "2026.9.29.5"
+  #
+  # 2026.9.30.1 (mcpp-community/mcpp#743): a build names each package when it
+  # does work, the live display is drawn in one write, a path or git
+  # dependency's bare key states only its short name, and the lock file keeps
+  # one entry per identity.
+  MCPP_VERSION: "2026.9.30.1"
 
 jobs:
   lint:

index.toml

@@ -145,7 +145,13 @@
 # which runs every member on every platform with it. The release changes no
 # descriptor grammar; the build's human output changes, and no check here
 # reads it.
+# ── 2026-09-30: latest_mcpp -> 2026.9.30.1, min_mcpp unchanged ─────────────
+#
+# Moved in the pull request that moves validate.yml's pin to 2026.9.30.1,
+# which runs every member on every platform with it. The release changes no
+# descriptor grammar; the build's human output changes again, and no check
+# here reads it.
 [index]
 spec        = "1"
 min_mcpp    = "2026.9.18.3"
-latest_mcpp = "2026.9.29.5"
+latest_mcpp = "2026.9.30.1"