Intel Iris Xe renders on the X1E — a graphics prerequisite, not a desktop

The Intel Iris Xe iGPU on a ThinkPad X1 Extreme (Alder Lake-P) now does real graphics under Solnix. Mesa's iris driver renders OpenGL ES 3.2 on the GPU and reads the result back correctly — forcing the software renderer instead changes the reported renderer name, which confirms the hardware path was the one used. Vulkan enumerates the device as "Intel Graphics (ADL GT2)". And the kernel can place its own framebuffer on the laptop panel (the brief orange screen) and hand the console back. Two illumos-specific blockers were fixed along the way so the compositor can even open the GPU: seatd now recognises /dev/dri devices once illumos resolves them to their /devices path, and a Rust DRM library that assumed Linux's device numbering was corrected. The honest status: COSMIC compiles and now opens the GPU and begins setting up the display, but it does NOT yet draw a frame. It is blocked because programs cannot yet share GPU buffers between each other — the kernel cannot create dma-buf handles, a feature the illumos DRM port has never had, and Mesa disables the feature on illumos as a result. A compositor needs both. The work ahead is in three honest steps: add dma-buf to the kernel (with a test that the unpatched driver still fails), enable Mesa's dma-buf path on illumos plus three smaller fixes in libdrm, the i915 driver and Mesa's build, and only then run COSMIC on the real display. There is no graphical desktop on Solnix today; this is the groundwork for one.