feat: full auto-install chain for all platforms

- Wire ensure_claude_code() into cmd_update() — auto npm install if missing
- uclaude_install.sh: auto-install git, python3, curl via apt/dnf/yum/brew
- uclaude_update.bat: prereq checks with winget install suggestions
- uclaude_update.ps1: auto-install via winget (git, python, node)
- install_node(): macOS support via brew, RHEL/Fedora via rpm.nodesource
- Increased npm install timeout to 300s for slow connections

claude/uclaude_update.ps1

@@ -6,10 +6,56 @@ $ScriptDir = Split-Path -Parent $MyInvocation.MyCommand.Path
 $RepoRoot = Split-Path -Parent $ScriptDir
 Set-Location $RepoRoot
 
-# Pull latest artifacts
+# ---- Check prerequisites ----
+
+function Test-Command($cmd) {
+    return [bool](Get-Command $cmd -ErrorAction SilentlyContinue)
+}
+
+function Install-WithWinget($id, $name) {
+    if (Test-Command "winget") {
+        Write-Host "  Installing $name via winget..." -ForegroundColor Yellow
+        winget install --id $id --accept-package-agreements --accept-source-agreements -e
+        # Refresh PATH
+        $env:Path = [System.Environment]::GetEnvironmentVariable("Path", "Machine") + ";" + [System.Environment]::GetEnvironmentVariable("Path", "User")
+        return $true
+    }
+    return $false
+}
+
+# Git
+if (-not (Test-Command "git")) {
+    Write-Host "  git not found." -ForegroundColor Red
+    if (-not (Install-WithWinget "Git.Git" "Git")) {
+        Write-Host "  Install manually: https://git-scm.com/download/win" -ForegroundColor Yellow
+        exit 1
+    }
+}
+
+# Python
+$hasPython = (Test-Command "python3") -or (Test-Command "python")
+if (-not $hasPython) {
+    Write-Host "  Python not found." -ForegroundColor Red
+    if (-not (Install-WithWinget "Python.Python.3.12" "Python 3.12")) {
+        Write-Host "  Install manually: https://www.python.org/downloads/" -ForegroundColor Yellow
+        exit 1
+    }
+}
+
+# Node.js
+if (-not (Test-Command "node")) {
+    Write-Host "  Node.js not found." -ForegroundColor Yellow
+    if (-not (Install-WithWinget "OpenJS.NodeJS" "Node.js")) {
+        Write-Host "  Install manually: https://nodejs.org/" -ForegroundColor Yellow
+    }
+}
+
+# ---- Pull latest artifacts ----
+
 git pull --quiet 2>$null
 
-# Check admin
+# ---- Check admin ----
+
 $isAdmin = ([Security.Principal.WindowsPrincipal] [Security.Principal.WindowsIdentity]::GetCurrent()).IsInRole([Security.Principal.WindowsBuiltInRole]::Administrator)
 if (-not $isAdmin) {
     Write-Host "Re-running as Administrator..." -ForegroundColor Yellow
@@ -17,5 +63,7 @@ if (-not $isAdmin) {
     exit
 }
 
-# Run updater
-& python claude\uclaude_updater.py @args
+# ---- Run updater ----
+
+$pythonCmd = if (Test-Command "python3") { "python3" } else { "python" }
+& $pythonCmd claude\uclaude_updater.py @args