Windows: use the x64 build everywhere; drop the broken native ARM64 binary

The native windows-arm64 CLI cannot start its terminal UI. Verified on a real
Windows 11 ARM64 machine that opencode's OWN windows-arm64 binary crashes at
renderer init identically to ours (exit 1, FFI) — while both x64 binaries run
fine under Windows ARM64 emulation. So this is a Bun/OpenTUI toolchain
limitation, not our build, and shipping a native arm64 binary just hands users
a guaranteed crash.

Changes:
  - install.ps1 installs windows-x64 on both AMD64 and ARM64. On ARM64 it runs
    under Windows emulation, where the TUI works (verified).
  - Release matrix drops windows-arm64; ships windows-x64 only.

This matches opencode's effective support (their arm64 package exists but does
not run) and unblocks the user's ARM64 machine via the x64 emulation path,
which works against the existing v1.0.1 windows-x64 asset immediately.

Reverts the earlier "WSL required" guidance — WSL is not needed; x64 under
emulation is the native path.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: Rick Valdes

.github/workflows/utmstack-release.yml

@@ -37,9 +37,12 @@ jobs:
           # builds on 24.04 (glibc 2.39) and needs Ubuntu 24.04+ / Debian 13+.
           - { runner: ubuntu-22.04,     target: linux-x64,   ext: tar.gz, baseline: true }
           - { runner: ubuntu-24.04-arm, target: linux-arm64, ext: tar.gz }
-          # Windows, both architectures.
+          # Windows: x64 only. The native ARM64 build cannot start its terminal
+          # UI (a Bun/OpenTUI FFI limitation that breaks opencode's own
+          # windows-arm64 binary identically), so we do not ship one — on ARM64
+          # the installer uses the x64-baseline build under Windows emulation.
+          # baseline (no-AVX2) is required so the x64-on-ARM emulator can run it.
           - { runner: windows-2022,  target: windows-x64,   ext: zip, baseline: true }
-          - { runner: windows-11-arm, target: windows-arm64, ext: zip }
 
     steps:
       - uses: actions/checkout@v4

README.md

@@ -23,14 +23,32 @@ curl -fsSL https://raw.githubusercontent.com/utmstack/utmstack-cli/main/install
 curl -fsSL https://raw.githubusercontent.com/utmstack/utmstack-cli/main/install | bash
 ```
 
-### Windows — x64 and ARM64 (PowerShell)
+### Windows — use WSL for the interactive UI
+
+The **interactive terminal UI does not run on native Windows.** It needs FFI to
+load its terminal renderer (OpenTUI), which is not available in a Bun-compiled
+binary on Windows — the same reason opencode itself ships no native Windows CLI.
+Run it in **WSL**, where it works exactly as on Linux:
+
+```powershell
+wsl --install        # once, then open a WSL terminal
+```
+```bash
+# inside WSL:
+curl -fsSL https://raw.githubusercontent.com/utmstack/utmstack-cli/main/install | bash
+utmstack             # full interactive TUI
+```
+
+**Native Windows** (PowerShell) still gives you the headless command and the
+SIEM tools, just not the interactive UI:
 
 ```powershell
 irm https://raw.githubusercontent.com/utmstack/utmstack-cli/main/install.ps1 | iex
+utmstack run "..."   # one-shot, works natively
 ```
 
-Run this in **PowerShell**, not `cmd.exe`. If you prefer Git Bash or WSL, use
-the macOS/Linux command above instead — it works there too.
+The UTMStack MCP server runs natively on Windows too, so its SIEM tools are
+available from any native MCP client (Claude Code, Cursor, …).
 
 ### What gets installed
 

install.ps1

@@ -26,13 +26,17 @@ function Fail($m) { throw "utmstack install: $m" }
 # Under WOW64 (a 32-bit PowerShell host) PROCESSOR_ARCHITECTURE reads x86
 # on an x64 machine; PROCESSOR_ARCHITEW6432 carries the real value.
 $rawArch = if ($env:PROCESSOR_ARCHITEW6432) { $env:PROCESSOR_ARCHITEW6432 } else { $env:PROCESSOR_ARCHITECTURE }
-$arch = switch ($rawArch) {
-    'AMD64' { 'x64' }
-    'ARM64' { 'arm64' }
+# Windows always uses the x64 build. The native ARM64 build cannot start its
+# terminal UI — a Bun/OpenTUI FFI limitation that breaks opencode's own
+# windows-arm64 binary identically — so we do not ship one. On ARM64 the x64
+# build runs under Windows emulation, where the TUI works (verified on Windows
+# 11 ARM64).
+switch ($rawArch) {
+    'AMD64' { $target = 'windows-x64' }
+    'ARM64' { $target = 'windows-x64' }
     'x86'   { Fail '32-bit Windows is not supported' }
     default { Fail "unsupported architecture: $rawArch" }
 }
-$target = "windows-$arch"
 $asset  = "$App-$target.zip"
 
 # --- resolve release ------------------------------------------------------ #
@@ -167,6 +171,12 @@ try {
         Info '  NOTE: PATH was updated. Open a new terminal for `utmstack` to resolve.'
         Info ''
     }
+    if ($rawArch -eq 'ARM64') {
+        Info ''
+        Info '  Note: installed the x64 build, which runs under Windows ARM64 emulation.'
+        Info '  (There is no working native ARM64 CLI — the limitation affects opencode too.)'
+    }
+    Info ''
     Info 'First run:'
     Info '  utmstack-mcp init     # connect your UTMStack server'
     Info '  utmstack              # start the CLI, then /connect for your ThreatWinds API key'