feat: add 'ccs update' command with smart update notifications

Add comprehensive update functionality with intelligent notification system.
Supports manual update checking, automatic notifications every 24h, and works
across npm and direct installations with proper error handling.

Closes #12

lib/ccs.ps1

@@ -12,7 +12,7 @@ param(
 $ErrorActionPreference = "Stop"
 
 # Version (updated by scripts/bump-version.sh)
-$CcsVersion = "4.1.6"
+$CcsVersion = "4.2.0"
 $ScriptDir = Split-Path -Parent $MyInvocation.MyCommand.Path
 $ConfigFile = if ($env:CCS_CONFIG) { $env:CCS_CONFIG } else { "$env:USERPROFILE\.ccs\config.json" }
 $ProfilesJson = "$env:USERPROFILE\.ccs\profiles.json"
@@ -246,6 +246,7 @@ function Show-Help {
     Write-ColorLine "Diagnostics:" "Cyan"
     Write-ColorLine "  ccs doctor                  Run health check and diagnostics" "Yellow"
     Write-ColorLine "  ccs sync                    Sync delegation commands and skills" "Yellow"
+    Write-ColorLine "  ccs update                  Update CCS to latest version" "Yellow"
     Write-Host ""
 
     Write-ColorLine "Flags:" "Cyan"
@@ -1031,6 +1032,132 @@ function Sync-Run {
     Write-Host ""
 }
 
+# --- Update Command ---
+
+function Update-Run {
+    Write-Host ""
+    Write-Host "Checking for updates..." -ForegroundColor Cyan
+    Write-Host ""
+
+    # Detect installation method
+    $InstallMethod = "direct"
+    try {
+        $NpmList = npm list -g @kaitranntt/ccs 2>&1
+        if ($LASTEXITCODE -eq 0) {
+            $InstallMethod = "npm"
+        }
+    } catch {
+        # npm not available or not installed via npm
+    }
+
+    # Fetch latest version from appropriate source
+    $LatestVersion = ""
+    try {
+        if ($InstallMethod -eq "npm") {
+            # Check npm registry for npm installations
+            $Response = Invoke-RestMethod -Uri "https://registry.npmjs.org/@kaitranntt/ccs/latest" -TimeoutSec 5
+            $LatestVersion = $Response.version
+        } else {
+            # Check GitHub releases for direct installations
+            $Response = Invoke-RestMethod -Uri "https://api.github.com/repos/kaitranntt/ccs/releases/latest" -TimeoutSec 5
+            $LatestVersion = $Response.tag_name -replace '^v', ''
+        }
+    } catch {
+        Write-Host "[!] Unable to check for updates" -ForegroundColor Yellow
+        Write-Host ""
+        Write-Host "Try manually:"
+        if ($InstallMethod -eq "npm") {
+            Write-Host "  npm install -g @kaitranntt/ccs@latest" -ForegroundColor Yellow
+        } else {
+            Write-Host "  irm ccs.kaitran.ca/install | iex" -ForegroundColor Yellow
+        }
+        Write-Host ""
+        exit 1
+    }
+
+    # Compare versions
+    if ($LatestVersion -eq $CcsVersion) {
+        Write-Host "[OK] You are already on the latest version ($CcsVersion)" -ForegroundColor Green
+        Write-Host ""
+        exit 0
+    }
+
+    # Check if update available
+    $CurrentParts = $CcsVersion.Split('.')
+    $LatestParts = $LatestVersion.Split('.')
+
+    $IsNewer = $false
+    for ($i = 0; $i -lt 3; $i++) {
+        $Current = [int]$CurrentParts[$i]
+        $Latest = [int]$LatestParts[$i]
+
+        if ($Latest -gt $Current) {
+            $IsNewer = $true
+            break
+        } elseif ($Latest -lt $Current) {
+            break
+        }
+    }
+
+    if (-not $IsNewer) {
+        Write-Host "[OK] You are on version $CcsVersion (latest is $LatestVersion)" -ForegroundColor Green
+        Write-Host ""
+        exit 0
+    }
+
+    Write-Host "[i] Update available: $CcsVersion → $LatestVersion" -ForegroundColor Yellow
+    Write-Host ""
+
+    # Perform update based on installation method
+    if ($InstallMethod -eq "npm") {
+        Write-Host "Updating via npm..." -ForegroundColor Cyan
+        Write-Host ""
+
+        try {
+            npm install -g @kaitranntt/ccs@latest
+            if ($LASTEXITCODE -eq 0) {
+                Write-Host ""
+                Write-Host "[OK] Update successful!" -ForegroundColor Green
+                Write-Host ""
+                Write-Host "Run ccs --version to verify" -ForegroundColor Yellow
+                Write-Host ""
+                exit 0
+            } else {
+                throw "npm install failed"
+            }
+        } catch {
+            Write-Host ""
+            Write-Host "[X] Update failed" -ForegroundColor Red
+            Write-Host ""
+            Write-Host "Try manually:"
+            Write-Host "  npm install -g @kaitranntt/ccs@latest" -ForegroundColor Yellow
+            Write-Host ""
+            exit 1
+        }
+    } else {
+        Write-Host "Updating via installer..." -ForegroundColor Cyan
+        Write-Host ""
+
+        try {
+            irm ccs.kaitran.ca/install | iex
+            Write-Host ""
+            Write-Host "[OK] Update successful!" -ForegroundColor Green
+            Write-Host ""
+            Write-Host "Run ccs --version to verify" -ForegroundColor Yellow
+            Write-Host ""
+            exit 0
+        } catch {
+            Write-Host ""
+            Write-Host "[X] Update failed" -ForegroundColor Red
+            Write-Host ""
+            Write-Host "Try manually:"
+            Write-Host "  irm ccs.kaitran.ca/install | iex" -ForegroundColor Yellow
+            Write-Host ""
+            exit 1
+        }
+    }
+}
+
 # --- Auth Commands (Phase 3) ---
 
 function Show-AuthHelp {
@@ -1519,6 +1646,12 @@ if ($RemainingArgs.Count -gt 0 -and ($RemainingArgs[0] -eq "sync" -or $Remaining
     exit 0
 }
 
+# Special case: update command
+if ($RemainingArgs.Count -gt 0 -and ($RemainingArgs[0] -eq "update" -or $RemainingArgs[0] -eq "--update")) {
+    Update-Run
+    exit 0
+}
+
 # Run auto-recovery before main logic
 if (-not (Invoke-AutoRecovery)) {
     Write-ErrorMsg "Auto-recovery failed. Check permissions."