Audio render-hook M4: audio panel source indicator + stream-count debug view

Surfaces the render-hook diagnostics in the Audio panel.

- HookStatusView / IpcServer::hook_status(): carry audio_streams_seen +
  audio_streams[] from the hook's back-channel.
- InjectionPanel: expose hook_status() so the audio panel can read the counts.
- AudioPanel::draw_ui(HookStatusView): show the active Source (green Hooked
  vs amber Loopback); only warn about the local echo on the loopback path. Add
  the required render-stream table: one row per stream with format, cumulative
  frames, the primary tagged, and a live/idle dot derived from frame-count
  deltas. Notes overflow when the game exceeds kMaxAudioStreams slots.

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

host/src/audio_panel.cpp

@@ -1,11 +1,35 @@
 #include "audio_panel.hpp"
 
+#include <algorithm>
+
 #include "imgui.h"
 
+#include <mmreg.h>
+
 namespace coop
 {
 
-void AudioPanel::draw_ui()
+namespace
+{
+
+const char* format_tag_name(std::uint32_t tag)
+{
+	switch (tag)
+	{
+	case WAVE_FORMAT_PCM:
+		return "PCM";
+	case WAVE_FORMAT_IEEE_FLOAT:
+		return "float";
+	case WAVE_FORMAT_EXTENSIBLE:
+		return "ext";
+	default:
+		return "?";
+	}
+}
+
+} // namespace
+
+void AudioPanel::draw_ui(const HookStatusView& status)
 {
 	const bool have_target = target_ != nullptr && IsWindow(target_);
 	DWORD pid = 0;
@@ -44,15 +68,79 @@ void AudioPanel::draw_ui()
 
 	if (mirror_.running())
 	{
+		const AudioMirror::Source src = mirror_.source();
+		const bool hooked = src == AudioMirror::Source::Hooked;
 		ImGui::TextColored(ImVec4(0.4f, 1.0f, 0.4f, 1.0f), "Mirroring  %u Hz, %u ch",
 		                   mirror_.sample_rate(), mirror_.channels());
+		ImGui::Text("Source:");
+		ImGui::SameLine();
+		ImGui::TextColored(hooked ? ImVec4(0.4f, 1.0f, 0.4f, 1.0f) : ImVec4(1.0f, 0.8f, 0.3f, 1.0f), "%s",
+		                   mirror_.source_name());
 	}
-	const std::string status = mirror_.status();
-	if (!status.empty())
+	const std::string mirror_status = mirror_.status();
+	if (!mirror_status.empty())
 	{
-		ImGui::TextWrapped("%s", status.c_str());
+		ImGui::TextWrapped("%s", mirror_status.c_str());
+	}
+
+	// Only the loopback path leaves the game audible locally (the echo); the
+	// hooked path silences it, so don't warn there.
+	if (mirror_.source() == AudioMirror::Source::Loopback)
+	{
+		ImGui::TextDisabled("Game audio also plays locally (echo). Inject the hook to remove it.");
+	}
+
+	// --- Render-stream debug view -----------------------------------------
+	// The hook counts every render stream the game creates, even with mirroring
+	// off. v1 captures only the first ("primary"); this makes multi-stream games
+	// obvious so we know if/when that needs revisiting.
+	ImGui::Separator();
+	ImGui::Text("Render streams: %u", status.audio_streams_seen);
+	if (status.audio_streams_seen > kMaxAudioStreams)
+	{
+		ImGui::SameLine();
+		ImGui::TextDisabled("(showing first %u)", kMaxAudioStreams);
+	}
+
+	const std::uint32_t rows = std::min<std::uint32_t>(status.audio_streams_seen, kMaxAudioStreams);
+	if (rows > 0 &&
+	    ImGui::BeginTable("audio_streams", 5, ImGuiTableFlags_Borders | ImGuiTableFlags_SizingFixedFit))
+	{
+		ImGui::TableSetupColumn("#");
+		ImGui::TableSetupColumn("role");
+		ImGui::TableSetupColumn("format");
+		ImGui::TableSetupColumn("frames");
+		ImGui::TableSetupColumn("live");
+		ImGui::TableHeadersRow();
+		for (std::uint32_t i = 0; i < rows; ++i)
+		{
+			const AudioStreamInfo& s = status.audio_streams[i];
+			const bool live = s.frames_rendered > prev_frames_[i];
+			prev_frames_[i] = s.frames_rendered;
+
+			ImGui::TableNextRow();
+			ImGui::TableNextColumn();
+			ImGui::Text("%u", i);
+			ImGui::TableNextColumn();
+			ImGui::TextColored(s.is_primary ? ImVec4(0.4f, 1.0f, 0.4f, 1.0f) : ImVec4(0.7f, 0.7f, 0.7f, 1.0f),
+			                   "%s", s.is_primary ? "primary" : "extra");
+			ImGui::TableNextColumn();
+			ImGui::Text("%u Hz %uch %u-bit %s", s.sample_rate, s.channels, s.bits,
+			            format_tag_name(s.format_tag));
+			ImGui::TableNextColumn();
+			ImGui::Text("%llu", static_cast<unsigned long long>(s.frames_rendered));
+			ImGui::TableNextColumn();
+			if (live)
+			{
+				ImGui::TextColored(ImVec4(0.4f, 1.0f, 0.4f, 1.0f), "●");
+			}
+			else
+			{
+				ImGui::TextDisabled("idle");
+			}
+		}
+		ImGui::EndTable();
 	}
-	ImGui::TextDisabled("Game audio also plays locally (double audio).");
 
 	ImGui::End();
 }