fix: decode native output as UTF-8 on Windows, so progress bars stop mojibaking

winget draws its progress bar with UTF-8 block characters, but PowerShell
decodes native output using the console codepage (437), turning each block into
three Latin characters and burying the real messages. Sets
[Console]::OutputEncoding to UTF-8 in install-windows.ps1, and chcp 65001 in
ncp.cmd for the check marks and em-dashes ncp.py prints.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

install-windows.ps1

@@ -18,6 +18,14 @@ Set-StrictMode -Version Latest
 $ErrorActionPreference = "Stop"
 $RepoRoot = $PSScriptRoot
 
+# winget draws its progress bar with U+2588/U+2592 block characters in UTF-8,
+# but PowerShell decodes a native command's output using the CONSOLE codepage
+# (437 on a US box). The three UTF-8 bytes of a block then render as "Gamma u e"
+# - the log fills with 'GubebGubeb...' mojibake and the real messages get lost
+# in it. Decoding as UTF-8 is the fix; it is per-process and does not touch the
+# user's console settings.
+[Console]::OutputEncoding = [System.Text.Encoding]::UTF8
+
 # -- Helpers -------------------------------------------------------------------
 function Write-Step { param([string]$Msg) Write-Host "`n==> $Msg" -ForegroundColor Cyan }
 function Write-OK   { param([string]$Msg) Write-Host "    ok:   $Msg" -ForegroundColor Green }

management/ncp.cmd

@@ -7,6 +7,13 @@ REM the machine PATH. ncp.ps1 stays for pwsh-on-Linux, where there is no PATH sh
 REM
 REM ASCII only, same rule as the .ps1 files - a test in tests/test_smoke.py enforces it.
 setlocal
+REM ncp.py pins its stdout to UTF-8 (it prints check marks and em-dashes, and a
+REM redirected stdout would otherwise raise UnicodeEncodeError). A console still
+REM on codepage 437 renders those bytes as mojibake, so switch it to UTF-8 here.
+REM ponytail: chcp changes the calling console's codepage and does not restore
+REM it on exit. Harmless in practice; if that ever matters, set the console CP
+REM from inside ncp.py with ctypes SetConsoleOutputCP instead.
+chcp 65001 >nul 2>&1
 set "ROOT=%~dp0.."
 REM System Python fallback so backup/restore work before the venv exists; those
 REM delegate to the stdlib-only bin/sync.py. Mirrors the same fallback in ncp.ps1.