feat: add provider-specific terminal button

Add a terminal button next to each provider card that opens a new terminal
window with that provider's specific API configuration. This allows using
different providers independently without changing the global setting.

Changes:
- Backend: Add `open_provider_terminal` command that extracts provider
  config and creates a temporary claude settings file
- Frontend: Add terminal button to provider cards with proper callback
  propagation through component hierarchy
- Support macOS (Terminal.app), Linux (gnome-terminal, konsole, etc.),
  and Windows (cmd)

Each provider gets a unique config file named `claude_<providerId>_<pid>.json`
in the temp directory, containing the provider's API configuration.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

src/components/providers/ProviderActions.tsx

@@ -6,6 +6,7 @@ import {
   Loader2,
   Play,
   Plus,
+  Terminal,
   TestTube2,
   Trash2,
 } from "lucide-react";
@@ -23,6 +24,7 @@ interface ProviderActionsProps {
   onTest?: () => void;
   onConfigureUsage: () => void;
   onDelete: () => void;
+  onOpenTerminal?: () => void;
   // 故障转移相关
   isAutoFailoverEnabled?: boolean;
   isInFailoverQueue?: boolean;
@@ -39,6 +41,7 @@ export function ProviderActions({
   onTest,
   onConfigureUsage,
   onDelete,
+  onOpenTerminal,
   // 故障转移相关
   isAutoFailoverEnabled = false,
   isInFailoverQueue = false,
@@ -171,6 +174,21 @@ export function ProviderActions({
           <BarChart3 className="h-4 w-4" />
         </Button>
 
+        {onOpenTerminal && (
+          <Button
+            size="icon"
+            variant="ghost"
+            onClick={onOpenTerminal}
+            title={t("provider.openTerminal", "打开终端")}
+            className={cn(
+              iconButtonClass,
+              "hover:text-emerald-600 dark:hover:text-emerald-400",
+            )}
+          >
+            <Terminal className="h-4 w-4" />
+          </Button>
+        )}
+
         <Button
           size="icon"
           variant="ghost"