docs: rugnux is tested on Arm (DGX Spark) and on Apple Silicon

The install and release pages said the aarch64 build was not exercised on Arm hardware. rc176's timing
benchmark passes on a DGX Spark (GB10) with a native build of the same source, and on an Apple M-series
Mac mini on Metal and CPU-only; the pages now say so, keeping that the aarch64 archive itself is
cross-compiled in CI. The macOS row also names the model density among the Metal engines.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PXc1zD1yxHqaR1DGdCTHL4

docs/RELEASE_CONTENTS.md

@@ -113,7 +113,8 @@ is no CUDA-toolkit version requirement on the host.
 | any `cpu` / `nocuda` variant, and everything for macOS | — | — | none |
 
 The aarch64 build is cross-compiled and verified in CI to be Arm, self-contained and to carry both
-GPU targets, but it is **not exercised on hardware** — CI has no GH200 or Spark runner.
+GPU targets. CI has no Arm runner; rugnux itself is tested on a DGX Spark (GB10), where the timing
+benchmark passes with a native build of the same source.
 
 **A V100 needs the CUDA 12 build.** CUDA 13 dropped offline compilation for Volta, and the PTX that a
 fatbin also carries only ever JIT-compiles *forwards*, so a CUDA 13 artefact contains nothing a V100

docs/RUGNUX_INSTALL.md

@@ -36,9 +36,9 @@ take the archive for your architecture from the Gitea release page:
 | Archive | For |
 | --- | --- |
 | `rugnux-<version>-linux-x86_64-cuda12.tgz` | 64-bit Intel/AMD Linux. Built on RHEL 8, so it runs on any newer Linux |
-| `rugnux-<version>-linux-aarch64-cuda13.tgz` | 64-bit Arm Linux — NVIDIA GH200 and DGX Spark. Built on Ubuntu 24.04, so it needs glibc 2.39 or newer. Cross-compiled and **not yet exercised on Arm hardware** |
+| `rugnux-<version>-linux-aarch64-cuda13.tgz` | 64-bit Arm Linux — NVIDIA GH200 and DGX Spark. Built on Ubuntu 24.04, so it needs glibc 2.39 or newer. Rugnux is tested on a DGX Spark (GB10): the timing benchmark passes with a native build of the same source; the archive itself is cross-compiled in CI |
 | `rugnux-<version>-win64-cuda13.zip` | 64-bit Windows |
-| `rugnux-<version>-macos-arm64-cpu.tgz` | macOS 13 (Ventura) or newer on Apple Silicon (M1 and newer). No CUDA on macOS: CPU, with Bragg integration and parts of molecular replacement on the Apple GPU (Metal). Intel Macs are not supported |
+| `rugnux-<version>-macos-arm64-cpu.tgz` | macOS 13 (Ventura) or newer on Apple Silicon (M1 and newer). No CUDA on macOS: CPU, with Bragg integration, the model density and the molecular-replacement rotation function on the Apple GPU (Metal). Tested on an Apple M-series Mac mini, where the timing benchmark passes on Metal and CPU-only. Intel Macs are not supported |
 
 **The archive has no top-level directory** — it unpacks straight into `bin/` and `share/`. Always
 give `tar` a destination of its own, or it will scatter those into whatever directory you are in: