feat(uninstall): add uninstall.ps1 script

Removes managed files, extension/skill ledger entries, semantic
retrieval, and the saved Quickupdate selection for a selected client,
reusing the same manifest-sync backup and warn-and-retain semantics as
install and update.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

scripts/uninstall.ps1

@@ -0,0 +1,74 @@
+[CmdletBinding()]
+param(
+    [switch]$DryRun,
+    [ValidateSet('Codex','Claude','Both')][string]$Client,
+    [switch]$Force,
+    [switch]$Summary
+)
+$ErrorActionPreference = 'Stop'
+$root = Split-Path $PSScriptRoot -Parent
+. (Join-Path $PSScriptRoot 'lib/plugins.ps1')
+. (Join-Path $PSScriptRoot 'lib/manifest.ps1')
+. (Join-Path $PSScriptRoot 'lib/install-targets.ps1')
+. (Join-Path $PSScriptRoot 'lib/semantic-retrieval.ps1')
+
+$Client = Read-InstallClient -Client $Client
+$homePath = [Environment]::GetFolderPath('UserProfile')
+$generated = Join-Path $root 'generated'
+$targets = @(Get-InstallTargets -Generated $generated -HomePath $homePath -Shell 'bash' -Client $Client)
+$installedTargets = @($targets | Where-Object { Test-Path -LiteralPath (Get-ManagedManifestPath $_.Destination) })
+
+if (-not $DryRun -and $installedTargets.Count -eq 0) { throw 'Not installed, nothing to uninstall.' }
+
+if (-not $DryRun -and -not $Force) {
+    if ([Console]::IsInputRedirected -or $env:CI -eq 'true' -or $env:AI_CONFIG_NO_INTERACTIVE -eq '1') {
+        throw 'Refusing to uninstall without confirmation in a non-interactive session. Pass -Force to proceed.'
+    }
+    Write-Host "This removes the managed configuration, extensions, and semantic retrieval setup for $Client under $homePath."
+    Write-Host 'Backups already on disk are kept; anything this setup never installed is left untouched.'
+    $confirm = [Console]::ReadLine()
+    if ($null -eq $confirm -or $confirm.Trim().ToLowerInvariant() -ne 'yes') {
+        Write-Output "Type 'yes' to continue: cancelled, nothing was removed."
+        exit 1
+    }
+}
+
+$stamp = Get-Date -Format 'yyyyMMdd-HHmmss'
+$emptySource = Join-Path ([System.IO.Path]::GetTempPath()) "ai-config-uninstall-$stamp"
+New-Item $emptySource -ItemType Directory -Force | Out-Null
+try {
+    foreach ($item in $targets) {
+        if (-not (Test-Path -LiteralPath (Get-ManagedManifestPath $item.Destination))) {
+            if (-not $Summary) { Write-Output "SKIP $($item.Destination) (not installed)" }
+            continue
+        }
+        Sync-ManagedDestination -Source $emptySource -Destination $item.Destination -Stamp $stamp `
+            -AiConfigRoot $item.Destination.Replace('\','/') -ShellCommand '' -PowerShellCommand '' -DryRun:$DryRun -Summary:$Summary
+        if (-not $DryRun) {
+            Remove-Item -LiteralPath (Get-ManagedManifestPath $item.Destination) -Force -ErrorAction SilentlyContinue
+            if (@(Get-ChildItem -LiteralPath $item.Destination -Force -ErrorAction SilentlyContinue).Count -eq 0) {
+                Remove-Item -LiteralPath $item.Destination -Force -ErrorAction SilentlyContinue
+            }
+        }
+    }
+} finally {
+    Remove-Item -LiteralPath $emptySource -Recurse -Force -ErrorAction SilentlyContinue
+}
+
+Sync-ConfiguredPlugins -RepositoryRoot $root -HomePath $homePath -Client $Client -DryRun:$DryRun -Summary:$Summary -Entries @()
+Sync-SemanticRetrieval -RepositoryRoot $root -HomePath $homePath -Client $Client -Enabled $false -DryRun:$DryRun -Summary:$Summary
+
+if (-not $DryRun) {
+    $remaining = @($targets | Where-Object { Test-Path -LiteralPath (Get-ManagedManifestPath $_.Destination) })
+    if ($remaining.Count -eq 0) {
+        $configRoot = Join-Path $homePath '.my-ai-configuration'
+        $selectionPath = Join-Path $configRoot 'selection.json'
+        if (Test-Path -LiteralPath $selectionPath) { Remove-Item -LiteralPath $selectionPath -Force }
+        if ((Test-Path -LiteralPath $configRoot) -and @(Get-ChildItem -LiteralPath $configRoot -Force -ErrorAction SilentlyContinue).Count -eq 0) {
+            Remove-Item -LiteralPath $configRoot -Force -ErrorAction SilentlyContinue
+        }
+    }
+}
+
+if ($Summary) { Write-Output "Uninstall: PASS | $Client$(if ($DryRun) { ', dry-run' })" } else { Write-Output ($(if ($DryRun) { 'PASS uninstall dry-run' } else { 'PASS uninstall' })) }
+exit 0