docs(linux): close Slice L0

memory/project_linux_graphical.md

@@ -0,0 +1,65 @@
+# Modern Runtime Linux graphical continuation
+
+## Current checkpoint
+
+Slice L0 completed at
+`66f114b258c0c37b51a7c0e04ca0d6441f4b1699`.
+
+The same `AcDream.App` now builds and publishes for `linux-x64`; there is no
+Linux gameplay or renderer fork.
+
+Canonical seams:
+
+- `AcDream.Runtime.Platform.ApplicationPathSet` owns XDG/Windows config, data,
+  cache, plugin, screenshot, and diagnostic paths for graphical and headless
+  hosts.
+- `AcDream.App.Platform.GraphicalHostPlatformServices` owns one startup OS,
+  architecture, RID, native-dependency manifest, path set, and pacing factory.
+- `PlatformFramePacingWaiterFactory` selects the existing Windows
+  high-resolution waitable timer or Linux
+  `LinuxMonotonicFramePacingWaiter`.
+- Linux waiting uses absolute `CLOCK_MONOTONIC` +
+  `clock_nanosleep(TIMER_ABSTIME)`, retries `EINTR`, does not busy-spin, and
+  rejects use after disposal.
+- Windows legacy `%LOCALAPPDATA%\acdream\settings.json` and
+  `keybinds.json` are copied only when the new roaming destination is absent.
+- bundled plugins are read beside the binary; user plugins are read from the
+  portable data root. A successful bundled ID wins; a failed load does not
+  reserve the ID.
+
+Exact L0 evidence:
+
+- Windows: Runtime 415, Headless 67, UI 543, App 3,736 / 3 skips, complete
+  Release 8,799 / 5 skips.
+- native Ubuntu/WSL: Runtime 415, Headless 67, UI 543, 14 L0 App tests.
+- exact framework-dependent `linux-x64` publish contains executable, managed
+  closure, GLFW, OpenAL Soft, cimgui, shaders, and smoke plugin/manifest;
+  direct `ldd` has no unresolved dependency.
+- closeout:
+  `docs/research/2026-07-27-slice-l0-platform-services.md`.
+
+Rollback:
+
+```text
+git revert 66f114b258c0c37b51a7c0e04ca0d6441f4b1699
+```
+
+## Next work — L1
+
+Do not claim Linux graphical support merely from publish success. L1 must:
+
+1. start the exact package under the available X11 and Wayland sessions;
+2. capture OS/display/compositor/GPU/driver/OpenGL vendor, renderer, version,
+   mandatory extensions, swap interval, refresh, DPI, and audio backend before
+   renderer construction;
+3. create the OpenGL 4.3 core context and reject missing bindless texture or
+   shader draw parameters with one actionable report;
+4. validate GLFW window/input callbacks, relative mouse/focus, framebuffer
+   sizing, clipboard, and monitor facts;
+5. initialize OpenAL fail-open exactly as current Windows behavior permits;
+6. render a packaged smoke scene, capture a screenshot, and close with zero
+   GL/OpenAL/window debt.
+
+Historical test-only issue: two installed-DAT App tests still hard-code
+`C:\Turbine\Asheron's Call`. They are not production blockers, but clean them
+before claiming the complete App test suite on a clean Linux runner.