emu: record the 2026-09-08 host-Vulkan retry, so nobody spends a boot on it

The comment invited a retry whenever mesa moves, and mesa moved
(26.1.7 -> 26.2.2). Retried: byte-identical fatal error, gfxstream still
cannot find a memory type for its ColorBuffers because Venus does not
support exporting VK_FORMAT_R8G8B8A8_UNORM the way it asks. Emulator
37.1.11 is still the newest offered and still ships only OpaqueFd/Metal/
none as external-memory modes, so there is no mode to switch to.

Comment only -- no behaviour change. Also records what the guest does get,
measured inside it: GLES on the host's real GPU through virgl, OpenGL ES
3.1, compute shaders available.

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

bin/emu

@@ -129,8 +129,15 @@ check_room() {
 # supported", then "Failed to find memory type for ColorBuffers", then the
 # emulator dies before adb ever sees it. GLES on the same driver is fine, and
 # is what the guest falls back to, so the only thing lost is Vulkan inside
-# the guest. Try dropping this whenever mesa moves: the failure is loud and
+# the guest. Try dropping this whenever mesa or the emulator package moves:
-# immediate, so it costs one boot to find out.
+# the failure is loud and immediate, so it costs one boot to find out.
+#
+# Retried 2026-09-08 on mesa 26.2.2 (was 26.1.7): identical fatal error, and
+# emulator 37.1.11 is still the newest offered, its libgfxstream_backend.so
+# still knowing only OpaqueFd/Metal/none as external-memory modes -- so there
+# is no mode to switch to and nothing to do here but wait. What the guest
+# does get, measured in it the same day: GLES on the host's real GPU through
+# virgl, reporting OpenGL ES 3.1 with compute shaders.
 GPU_HOST_FEATURES=${GPU_HOST_FEATURES:--feature -Vulkan}
 
 # An X server on this machine's GPU, started once and reused, or nothing.