fix(windows): stabilize install and prerelease versioning

lib/core/version.ps1

@@ -0,0 +1,41 @@
+# Mole - Version helpers
+# Provides a single source of truth for the Windows version string.
+
+#Requires -Version 5.1
+Set-StrictMode -Version Latest
+
+if ((Get-Variable -Name 'MOLE_VERSION_HELPERS_LOADED' -Scope Script -ErrorAction SilentlyContinue) -and $script:MOLE_VERSION_HELPERS_LOADED) {
+    return
+}
+$script:MOLE_VERSION_HELPERS_LOADED = $true
+
+$script:MoleDefaultVersion = "1.29.0"
+
+function Get-MoleVersionFilePath {
+    param([string]$RootDir)
+
+    if ([string]::IsNullOrWhiteSpace($RootDir)) {
+        return $null
+    }
+
+    return Join-Path $RootDir "VERSION"
+}
+
+function Get-MoleVersionString {
+    param(
+        [string]$RootDir,
+        [string]$DefaultVersion = $script:MoleDefaultVersion
+    )
+
+    $versionFile = Get-MoleVersionFilePath -RootDir $RootDir
+    if (-not $versionFile -or -not (Test-Path $versionFile)) {
+        return $DefaultVersion
+    }
+
+    $version = (Get-Content $versionFile -Raw).Trim()
+    if ([string]::IsNullOrWhiteSpace($version)) {
+        return $DefaultVersion
+    }
+
+    return $version
+}