Merge PR #288

# Conflicts:
#	docs/whats-new.md

docs/gpu-pipeline.md

@@ -55,7 +55,9 @@ Settings ▸ Performance ▸ *Use the GPU for rendering* unchecked (applied befo
 returns, successfully or not. If the marker is still there at the next launch, the process died inside
 the driver: LightCraft starts with GPU rendering off (the preference is saved unchecked), removes the
 marker and says so in a notice. Checking *Use the GPU for rendering* again tries the GPU once more
-(and re-arms the sentinel). Not with `LIGHTCRAFT_NO_PREFS` (tests, scripts). Killing the app during
+(and re-arms the sentinel). Not with `LIGHTCRAFT_NO_PREFS` (tests, scripts), and not in a `--memory` session,
+which writes nothing: it neither arms the sentinel nor removes a marker it finds (it still starts with GPU
+rendering off when one is there, and the next ordinary launch reports and clears it). Killing the app during
 the ~0.3 s of device creation, or two instances starting at the same moment, can trip it falsely —
 harmless: rendering is then on the CPU until the box is checked again. The sentinel only covers the
 compute device; a crash while the window's renderer starts is avoided by the backend defaults above

docs/whats-new.md

@@ -18,6 +18,9 @@
   labels 6–9, P / U and the rest did nothing, because macOS only passes ⌘ / ⌃ combinations and function keys
   to the menu bar and the app ignored those keys, assuming the menu bar would handle them. Keys outside the menus
   (Space, G, X, ⌫) and ⌘ shortcuts were not affected.
+- `--memory` sessions keep their promise to save nothing (issues #164, #169): UI changes made in one no longer
+  land in `ui.json` (where they replaced the saved settings), and the GPU crash sentinel no longer creates the
+  settings folder there. The same goes for the temporary session offered when the library can't be opened.
 - LightCraft no longer crashes at launch on Windows PCs whose Vulkan driver is broken (issue #136, e.g. some Intel UHD
   630 drivers): on Windows the window and GPU rendering use DirectX 12 only and never load the Vulkan driver unless
   asked to. `LIGHTCRAFT_GPU_BACKEND=dx12 | vulkan | metal | off` (or wgpu's `WGPU_BACKEND`, which GPU rendering