Generalize UI: general status by default, diagnostics behind Debug details

Rework the spike-era debug readouts into general-purpose status, with the
verbose diagnostics gated behind the menu bar's "Debug details" switch:

- Controllers (was "Phase 0 spike"): always shows slot/source + live
  buttons; the raw stick/trigger numbers are debug-only.
- Injection hook status: general view is attached + focus spoof + a single
  "Game reading controller: N polls/s" summary; the per-slot poll table,
  focus-API counts, and input-path detection are debug-only.
- Audio: general view adds a "Buffered: N ms" health/latency proxy
  (AudioMirror now tracks buffered audio in both render paths) and keeps the
  render-stream count; the per-stream table is debug-only.

Default overlay is now clean general status; flip Debug details for the full
diagnostics. Completes the "generalize the UI" roadmap task. All tests pass.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

host/src/audio/audio_loopback.hpp

@@ -61,6 +61,13 @@ public:
 		return channels_.load(std::memory_order_relaxed);
 	}
 
+	// Audio currently buffered between capture and the output device, in ms — a
+	// health/latency proxy (rises if the consumer can't keep up). 0 when stopped.
+	[[nodiscard]] unsigned buffered_ms() const
+	{
+		return buffered_ms_.load(std::memory_order_relaxed);
+	}
+
 	// Which capture path is active, for the UI's source indicator.
 	enum class Source
 	{
@@ -107,6 +114,7 @@ private:
 	std::atomic<Source> source_{Source::None};
 	std::atomic<unsigned> sample_rate_{0};
 	std::atomic<unsigned> channels_{0};
+	std::atomic<unsigned> buffered_ms_{0};
 
 	mutable std::mutex status_mutex_;
 	std::string status_;