feat(ui): implement pills-style AppSwitcher with consistent button widths

Replace segmented control with pills-style switcher for better visual consistency.

src/App.tsx

@@ -5,6 +5,7 @@ import ProviderList from "./components/ProviderList";
 import AddProviderModal from "./components/AddProviderModal";
 import EditProviderModal from "./components/EditProviderModal";
 import { ConfirmDialog } from "./components/ConfirmDialog";
+import { AppSwitcher } from "./components/AppSwitcher";
 import "./App.css";
 
 function App() {
@@ -182,39 +183,10 @@ function App() {
       <header className="app-header">
         <h1>{activeApp === "claude" ? "Claude Code" : "Codex"} 供应商切换器</h1>
         <div className="app-tabs">
-          <div className="segmented" role="tablist" aria-label="选择应用">
-            <span
-              className="segmented-thumb"
-              style={{
-                transform:
-                  activeApp === "claude"
-                    ? "translateX(0%)"
-                    : "translateX(100%)",
-              }}
-            />
-            <button
-              type="button"
-              role="tab"
-              aria-selected={activeApp === "claude"}
-              className={`segmented-item ${
-                activeApp === "claude" ? "active" : ""
-              }`}
-              onClick={() => setActiveApp("claude")}
-            >
-              Claude Code
-            </button>
-            <button
-              type="button"
-              role="tab"
-              aria-selected={activeApp === "codex"}
-              className={`segmented-item ${
-                activeApp === "codex" ? "active" : ""
-              }`}
-              onClick={() => setActiveApp("codex")}
-            >
-              Codex
-            </button>
-          </div>
+          <AppSwitcher
+            activeApp={activeApp}
+            onSwitch={setActiveApp}
+          />
         </div>
         <div className="header-actions">
           <button className="add-btn" onClick={() => setIsAddModalOpen(true)}>

src/components/AppSwitcher.css

@@ -0,0 +1,66 @@
+/* 药丸式切换按钮 */
+.switcher-pills {
+  display: inline-flex;
+  align-items: center;
+  gap: 12px;
+  background: rgba(255, 255, 255, 0.08);
+  padding: 6px 8px;
+  border-radius: 50px;
+  backdrop-filter: blur(10px);
+}
+
+.switcher-pill {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  gap: 8px;
+  padding: 8px 16px;
+  background: transparent;
+  border: none;
+  border-radius: 50px;
+  color: rgba(255, 255, 255, 0.6);
+  font-size: 14px;
+  font-weight: 600;
+  cursor: pointer;
+  transition: all 200ms ease;
+  min-width: 120px;
+}
+
+.switcher-pill:hover:not(.active) {
+  color: rgba(255, 255, 255, 0.8);
+  background: rgba(255, 255, 255, 0.05);
+}
+
+.switcher-pill.active {
+  background: rgba(255, 255, 255, 0.15);
+  color: white;
+  box-shadow: 
+    inset 0 1px 3px rgba(0, 0, 0, 0.1),
+    0 1px 0 rgba(255, 255, 255, 0.1);
+}
+
+.pill-dot {
+  width: 8px;
+  height: 8px;
+  border-radius: 50%;
+  background: currentColor;
+  opacity: 0.4;
+  transition: all 200ms ease;
+}
+
+.switcher-pill.active .pill-dot {
+  opacity: 1;
+  box-shadow: 0 0 8px currentColor;
+  animation: pulse 2s infinite;
+}
+
+.pills-divider {
+  width: 1px;
+  height: 20px;
+  background: rgba(255, 255, 255, 0.2);
+}
+
+@keyframes pulse {
+  0%, 100% { transform: scale(1); opacity: 1; }
+  50% { transform: scale(1.2); opacity: 0.8; }
+}

src/components/AppSwitcher.tsx

@@ -0,0 +1,36 @@
+import { AppType } from "../lib/tauri-api";
+import "./AppSwitcher.css";
+
+interface AppSwitcherProps {
+  activeApp: AppType;
+  onSwitch: (app: AppType) => void;
+}
+
+export function AppSwitcher({ activeApp, onSwitch }: AppSwitcherProps) {
+  const handleSwitch = (app: AppType) => {
+    if (app === activeApp) return;
+    onSwitch(app);
+  };
+
+  return (
+    <div className="switcher-pills">
+      <button
+        type="button"
+        className={`switcher-pill ${activeApp === "claude" ? "active" : ""}`}
+        onClick={() => handleSwitch("claude")}
+      >
+        <span className="pill-dot" />
+        <span>Claude Code</span>
+      </button>
+      <div className="pills-divider" />
+      <button
+        type="button"
+        className={`switcher-pill ${activeApp === "codex" ? "active" : ""}`}
+        onClick={() => handleSwitch("codex")}
+      >
+        <span className="pill-dot" />
+        <span>Codex</span>
+      </button>
+    </div>
+  );
+}