docs: describe SIMD-enabled release binaries

Author: XiaoConstantine

README.md

@@ -32,6 +32,10 @@ brew install sgrep
 sgrep setup
 ```
 
+Prebuilt x86_64 releases include Go 1.27's experimental portable SIMD TQ
+rotation kernels; Apple Silicon releases use NEON assembly. No runtime
+configuration is needed.
+
 See the [installation guide](https://xiaocui.me/sgrep/guides/getting-started/)
 for curl, Go, source builds, and sqlite-vec.
 

docs/content/guides/getting-started.md

@@ -34,8 +34,12 @@ go build -o sgrep ./cmd/sgrep
 Source builds require Go 1.27 or later. Prebuilt Intel macOS binaries support
 macOS 13 Ventura or later; Apple Silicon binaries require macOS 15.5 or later.
 
-Go 1.27's experimental portable SIMD kernels can be enabled for source builds
-on non-ARM64 systems. ARM64 builds continue to use the faster NEON assembly:
+Prebuilt x86_64 releases installed by Homebrew or the install script include
+Go 1.27's experimental portable SIMD TQ rotation kernels. ARM64 releases use
+NEON assembly, and neither installation needs runtime configuration. Dense dot
+products retain float64 scalar accumulation for score compatibility.
+
+Enable the same portable SIMD kernels for a non-ARM64 source build with:
 
 ```bash
 GOEXPERIMENT=simd go build -o sgrep ./cmd/sgrep