[Xget7]

Summary

Review leftovers from #39 and #40, Android only.

packages/splatkit-android/
├── README.md                    # alignment lines back above "Native tests on a device";
│                                # BUILD= set, network note, loop stops at the first failing test
└── src/main/cpp/rendering/vulkan/
    ├── cull/VulkanVisibilityPass.cpp   # kSetFamilies, kPoolSizeCount replace the bare 2s
    ├── frame/VulkanFrameCompute.h      # submission_ is one line, comment above it
    ├── layout/VulkanFrameSlots.h       # first sentence only
    └── VulkanSplatRenderer.cpp         # comment names the wait adoptWorld relies on
CONTRIBUTING.md, scripts/lint-cpp.sh    # the link step adds undefined references, not source paths
tests/.../VulkanRadixSortTest.cpp       # keyBitCount(input.keyBits)

World upload waits, from the code:

render(): uploadFinishedLoads()        # render thread, start of every frame, before draw
  uploadWorld / uploadLodWorld / createSlab
    waitIdle()                         # entry: the old world has no work in flight
    VulkanFrameCompute::create         # no queue submit of its own
    VulkanWorld::upload                # VulkanBuffer::upload: submit + vkWaitForFences
    waitIdle()                         # uploadWorld and createSlab only
    adoptWorld                         # replaces world_ and compute_

Nothing draws between the entry wait and adoptWorld (same thread), and the uploads in between are fenced, so the entry wait covers the replaced world.
The second wait in uploadWorld and createSlab is redundant, and uploadLodWorld already runs without it.
GPU synchronisation is unchanged here; the comment now says which wait is relied on, and the "may still be in flight" remarks on the second waits are gone because they said otherwise.

Evidence

• Before: the findings in final-fix-1 and final-fix-2 reviews (Minors 1-4 and 1-5).
  After: each is fixed; scripts/lint-cpp.sh exit 0, the Gradle release build and unit tests exit 0.
• Where it ran: the Mac host only, NDK 27.1.12297006 arm64 builds. No physical device was attached and no device run has happened; nothing here changes GPU commands, so device runs stay with the end session.
• Checks:
  • scripts/lint-cpp.sh: clang-format and clang-tidy clean, and all seven splatkit_vulkan_*_test link for arm64 through splatkit_android_tests.
  • ./gradlew :splatkit:assembleRelease :app:assembleRelease :splatkit:testDebugUnitTest --no-daemon: BUILD SUCCESSFUL.
  • Host WorldFrameCompletionTest compiled with the workflow's flags: exit 0.
  • The nine generated/shaders/*.spv hashes equal the recorded baseline.
  • The README loop checked with a stub adb that fails the second test: it stops there and exits 1.
  • Skipped: npm run check, npm run lint and sdk_harness.py (no TypeScript or engine change); the validation layer (no device).

Merge Danger

Door: two-way.

Comments, constant names, docs and a test printout only.

Blast Radius: negligible

The two new constants keep the values 2 and 2 the pool already used.