scripts: add Windows PowerShell entry point

CONTRIBUTING.md

@@ -22,6 +22,8 @@ Install QEMU and GDB with your system package manager:
 apt install qemu-system-arm gdb-multiarch
 ```
 
+> **Windows:** use Git Bash and the `./scripts/lych` commands below, or PowerShell with `.\scripts\lych.ps1` instead. The two scripts expose the same commands.
+
 ## Getting the Source
 
 ```sh

README.md

@@ -38,6 +38,8 @@ Install QEMU and GDB through your system package manager, e.g.:
 apt install qemu-system-arm gdb-multiarch
 ```
 
+> **Windows:** run the same commands from Git Bash using `./scripts/lych`, or from PowerShell using `.\scripts\lych.ps1`. The two scripts are equivalent.
+
 ### Build
 
 ```sh
@@ -76,7 +78,7 @@ The first starts QEMU paused with a GDB stub on `tcp::1234`; the second attaches
 ./scripts/lych clean
 ```
 
-All development flows go through `./scripts/lych` instead of raw `qemu-system-aarch64` and `gdb-multiarch` invocations. QEMU arguments, the CPU model, and debug options are kept in one place so they change in only one file when the platform or workflow changes.
+All development flows go through the `scripts/` entry points — `./scripts/lych` (Git Bash, Linux, macOS) or `.\scripts\lych.ps1` (Windows PowerShell) — instead of raw `qemu-system-aarch64` and `gdb-multiarch` invocations. QEMU arguments, the CPU model, and debug options are kept in one place so they change in only one file when the platform or workflow changes.
 
 ## Repository Layout
 

scripts/lych.ps1

@@ -0,0 +1,71 @@
+param(
+    [Parameter(Position = 0)]
+    [string]$Command
+)
+
+Set-StrictMode -Version Latest
+$ErrorActionPreference = 'Stop'
+
+$Project = Split-Path -Parent (Split-Path -Parent $MyInvocation.MyCommand.Path)
+Write-Host "Project root: $Project" -ForegroundColor DarkGray
+
+switch ($Command) {
+    'build' {
+        cargo build --release
+    }
+
+    'run' {
+        cargo build --release
+
+        & qemu-system-aarch64 `
+            -M virt `
+            -cpu cortex-a72 `
+            -nographic `
+            -kernel $Project\target\aarch64-unknown-none\release\kernel
+        if ($LASTEXITCODE -ne 0) { exit $LASTEXITCODE }
+    }
+
+    'debug' {
+        cargo build --release
+
+        & qemu-system-aarch64 `
+            -M virt `
+            -cpu cortex-a72 `
+            -nographic `
+            -S `
+            -gdb tcp::1234 `
+            -kernel $Project\target\aarch64-unknown-none\release\kernel
+        if ($LASTEXITCODE -ne 0) { exit $LASTEXITCODE }
+    }
+
+    'gdb' {
+        & gdb-multiarch `
+            $Project\target\aarch64-unknown-none\release\kernel `
+            -ex 'target remote :1234'
+        if ($LASTEXITCODE -ne 0) { exit $LASTEXITCODE }
+    }
+
+    'clean' {
+        cargo clean
+    }
+
+    'fmt' {
+        cargo fmt --all
+    }
+
+    'fmt-check' {
+        cargo fmt --all --check
+    }
+
+    default {
+        Write-Host 'Usage:' -ForegroundColor Yellow
+        Write-Host '  .\scripts\lych.ps1 build'
+        Write-Host '  .\scripts\lych.ps1 run'
+        Write-Host '  .\scripts\lych.ps1 debug'
+        Write-Host '  .\scripts\lych.ps1 gdb'
+        Write-Host '  .\scripts\lych.ps1 clean'
+        Write-Host '  .\scripts\lych.ps1 fmt'
+        Write-Host '  .\scripts\lych.ps1 fmt-check'
+        exit 1
+    }
+}