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

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

tests/connection-details.test.ts

@@ -0,0 +1,29 @@
+import { describe, expect, it } from "vitest";
+
+import { qualityLimitationSummary } from "../src/client/components/connection-details.ts";
+import { EMPTY_METRICS, type PeerSnapshot } from "../src/client/types.ts";
+
+function snapshot(qualityWarning: string | null): PeerSnapshot {
+  return {
+    peerId: "viewer-1",
+    connectionId: "connection-1",
+    connectionState: "connected",
+    iceConnectionState: "connected",
+    metrics: { ...EMPTY_METRICS, qualityLimitationReason: "bandwidth" },
+    error: null,
+    qualityWarning,
+  };
+}
+
+describe("progressive connection details", () => {
+  it("keeps one debounced quality warning outside the details panel", () => {
+    expect(
+      qualityLimitationSummary([
+        snapshot(null),
+        snapshot("持续受带宽限制，浏览器正在降低画面质量"),
+        snapshot("持续受编码性能限制，浏览器正在降低画面质量"),
+      ]),
+    ).toBe("持续受带宽限制，浏览器正在降低画面质量");
+    expect(qualityLimitationSummary([snapshot(null)])).toBeNull();
+  });
+});