fix(windows): correct window title and remove extra titlebar spacing

- Add missing "title" field to tauri.windows.conf.json to display
  "CC Switch" instead of default "Tauri app"
- Make DRAG_BAR_HEIGHT platform-aware: 0px on Windows/Linux (native
  titlebar), 28px on macOS (Overlay mode needs traffic light space)
- Apply same fix to FullScreenPanel component for consistency

Fixes the issue where Windows showed wrong title and had ~28px extra
blank space below the native titlebar introduced in v3.9.0.

src-tauri/tauri.windows.conf.json

@@ -4,6 +4,7 @@
     "windows": [
       {
         "label": "main",
+        "title": "CC Switch",
         "titleBarStyle": "Visible",
         "minWidth": 900,
         "minHeight": 600

src/App.tsx

@@ -31,6 +31,7 @@ import { useProxyStatus } from "@/hooks/useProxyStatus";
 import { useLastValidValue } from "@/hooks/useLastValidValue";
 import { extractErrorMessage } from "@/utils/errorUtils";
 import { cn } from "@/lib/utils";
+import { isWindows, isLinux } from "@/lib/platform";
 import { AppSwitcher } from "@/components/AppSwitcher";
 import { ProviderList } from "@/components/providers/ProviderList";
 import { AddProviderDialog } from "@/components/providers/AddProviderDialog";
@@ -60,7 +61,8 @@ type View =
   | "agents"
   | "universal";
 
-const DRAG_BAR_HEIGHT = 28; // px
+// macOS Overlay mode needs space for traffic light buttons, Windows/Linux use native titlebar
+const DRAG_BAR_HEIGHT = isWindows() || isLinux() ? 0 : 28; // px
 const HEADER_HEIGHT = 64; // px
 const CONTENT_TOP_OFFSET = DRAG_BAR_HEIGHT + HEADER_HEIGHT;
 

src/components/common/FullScreenPanel.tsx

@@ -3,6 +3,7 @@ import { createPortal } from "react-dom";
 import { motion, AnimatePresence } from "framer-motion";
 import { ArrowLeft } from "lucide-react";
 import { Button } from "@/components/ui/button";
+import { isWindows, isLinux } from "@/lib/platform";
 
 interface FullScreenPanelProps {
   isOpen: boolean;
@@ -12,7 +13,7 @@ interface FullScreenPanelProps {
   footer?: React.ReactNode;
 }
 
-const DRAG_BAR_HEIGHT = 28; // px - match App.tsx
+const DRAG_BAR_HEIGHT = isWindows() || isLinux() ? 0 : 28; // px - match App.tsx
 const HEADER_HEIGHT = 64; // px - match App.tsx
 
 /**