chore: merge feat/simple-entry-diagnostics into feat/clarity-quality-controls

# Conflicts:
#	src/client/pages/HostPage.tsx
#	src/client/styles.css

src/client/components/AppHeader.tsx

@@ -10,7 +10,7 @@ export function AppHeader({ status }: { status: ReactNode }) {
         </span>
         <span>Screener</span>
       </a>
-      <div className="header-status">{status}</div>
+      {status && <div className="header-status">{status}</div>}
     </header>
   );
 }

src/client/components/ConnectionDetailsToggle.tsx

@@ -0,0 +1,27 @@
+import type { ChangeEvent } from "react";
+
+interface ConnectionDetailsToggleProps {
+  checked: boolean;
+  onChange: (checked: boolean) => void;
+}
+
+export function ConnectionDetailsToggle({
+  checked,
+  onChange,
+}: ConnectionDetailsToggleProps) {
+  return (
+    <label
+      className="connection-details-toggle"
+      title="展开或隐藏连接的技术指标"
+    >
+      <input
+        type="checkbox"
+        checked={checked}
+        onChange={(event: ChangeEvent<HTMLInputElement>) =>
+          onChange(event.currentTarget.checked)
+        }
+      />
+      <span>显示连接详情</span>
+    </label>
+  );
+}

src/client/components/StatusBadge.tsx

@@ -39,7 +39,7 @@ export function PeerStatusBadge({
   state: RTCPeerConnectionState | "waiting";
 }) {
   const labels: Record<RTCPeerConnectionState | "waiting", BadgeProps> = {
-    waiting: { tone: "neutral", label: "等待画面" },
+    waiting: { tone: "neutral", label: "等待开始分享" },
     new: { tone: "neutral", label: "准备中" },
     connecting: { tone: "neutral", label: "正在连接" },
     connected: { tone: "good", label: "已连接" },

src/client/components/connection-details.ts

@@ -0,0 +1,12 @@
+import type { PeerSnapshot } from "../types";
+
+export function qualityLimitationSummary(
+  snapshots: readonly PeerSnapshot[],
+): string | null {
+  for (const snapshot of snapshots) {
+    if (snapshot.qualityWarning) {
+      return snapshot.qualityWarning;
+    }
+  }
+  return null;
+}