[MG_Impl, MG_IntegrationTest, ci] (P7): the first perturbation block's falsifier is the DirectVulkan entry

- measured with one block removed at a time: without the re-applied block both server halves drop to 1 (DirectGLES 1 / DirectVulkan 1, both entries red); without the first block DirectVulkan drops to 1 (red) while DirectGLES stays at 2 (green), because the GLES backend reads the pack field twice after the neutral pack is installed (3 = the saved-pack read + 2 post-install) and DirectVulkan once (2 = 1 + 1)
- so the >= 2 requirement falsifies the re-applied block on both backends and the first block on DirectVulkan; the CI step runs both backends and needs both, which it already does
- the scenario, hook and CI comments now say exactly that, instead of "removing either block drops it to 1"

.github/workflows/test.yml

@@ -1099,8 +1099,11 @@ jobs:
       # installs the neutral one, the backend's ReadPixels reads it after - and the hook perturbs
       # its oracle once per read, because the ID-49 overwrite inside the window wipes the first
       # perturbation before the second read's compare. A step satisfied by ONE line was satisfied
-      # by either perturbation alone and falsified neither; two is one per read, each falsified on
-      # its own. Measured at landing: 3 (DirectGLES) / 2 (DirectVulkan).
+      # by either perturbation alone and falsified neither. Measured at landing: 3 (DirectGLES,
+      # whose backend reads the field twice after the install) / 2 (DirectVulkan); without the
+      # re-applied perturbation both drop to 1, without the first one DirectVulkan drops to 1
+      # while DirectGLES stays at 2 - so BOTH backends are required, and the first perturbation's
+      # falsifier is the DirectVulkan entry.
       #
       # THE GREEN HALF is the lane run above: the same hook, the same window, with no corruption
       # armed, across 1070 entries at zero divergences.