feat(retrieval): offer device benchmark

scripts/lib/install-options.ps1

@@ -24,7 +24,23 @@ function Read-InstallOptions {
     return @{
         update_agents = Read-InstallBoolean -Prompt "Update selected agent CLIs ($Client)?" -Default $defaults.update_agents
         flashbang = Read-InstallBoolean -Prompt 'Enable the Flashbang notification hook?' -Default $defaults.flashbang
-        semantic_retrieval = Read-InstallBoolean -Prompt 'Enable Qwen3 embedding and reranking semantic retrieval?' -Default $defaults.semantic_retrieval
+        semantic_retrieval = Read-SemanticRetrievalOption -Default $defaults.semantic_retrieval -RepositoryRoot $RepositoryRoot -HomePath $HomePath
+    }
+}
+
+function Read-SemanticRetrievalOption {
+    param([bool]$Default,[string]$RepositoryRoot,[string]$HomePath)
+    $hint = if ($Default) { 'Y/n/a' } else { 'y/N/a' }
+    while ($true) {
+        Write-Host "Enable Qwen3 embedding and reranking semantic retrieval? [$hint] " -NoNewline
+        $answer = [Console]::ReadLine()
+        if ($null -eq $answer) { throw 'Input ended before semantic retrieval was confirmed.' }
+        switch ($answer.Trim().ToLowerInvariant()) {
+            '' { return $Default }
+            { $_ -in @('y', 'yes') } { return $true }
+            { $_ -in @('n', 'no') } { return $false }
+            { $_ -in @('a', 'auto') } { return Test-SemanticRetrievalDevice -RepositoryRoot $RepositoryRoot -HomePath $HomePath }
+        }
     }
 }