Audio: robust rate estimation + color-coded log levels

Harden the guessed-stream sample-rate measurement that produced wrong rates
(e.g. 44100 read as ~46205). New rate_estimator.hpp measures over longer
~0.5 s windows, rejects any window that doesn't snap to a standard rate
(standard rates are >8% apart, so a quantization/burst error big enough to
miss one lands in no-man's-land, never on a wrong neighbour), and requires
consensus across windows before committing. If consensus isn't reached it
commits a low-confidence estimate (new AudioFormat_LowConfidence, shown red)
rather than spinning or publishing garbage. Pure logic, unit-tested with
adversarial cadences (rate_estimator_test) incl. the real 46205 bug value.

Add log severity levels: hook logw/loge set LogRecord.level; the host Log
window colors warnings amber and errors red. The low-confidence rate logs a
warning. Protocol -> v15 (new format states); also reserves AudioFormat_Override.

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

host/src/audio_panel.cpp

@@ -44,6 +44,10 @@ const char* audio_format_state_name(std::uint32_t state)
 		return "measuring rate...";
 	case AudioFormat_Measured:
 		return "measured rate (ch/bits assumed)";
+	case AudioFormat_LowConfidence:
+		return "LOW-CONFIDENCE rate (verify / override)";
+	case AudioFormat_Override:
+		return "manual override";
 	default:
 		return "unknown";
 	}
@@ -55,11 +59,12 @@ ImVec4 audio_format_state_color(std::uint32_t state)
 	{
 	case AudioFormat_Exact:
 	case AudioFormat_Measured:
+	case AudioFormat_Override:
 		return kGreen; // format trustworthy -> correct pitch
 	case AudioFormat_Measuring:
 		return kAmber; // still verifying the rate
 	default:
-		return kRed; // unknown
+		return kRed; // unknown or low-confidence -> needs attention
 	}
 }
 

host/src/log_panel.cpp

@@ -21,7 +21,7 @@ void LogPanel::add_line(const LogRecord& rec)
 
 	char buf[256];
 	std::snprintf(buf, sizeof(buf), "[%8.3f] %s", secs, rec.text);
-	lines_.emplace_back(buf);
+	lines_.push_back({buf, rec.level});
 	while (lines_.size() > kMaxLines)
 	{
 		lines_.pop_front();
@@ -53,13 +53,24 @@ void LogPanel::draw()
 	if (ImGui::BeginChild("loglines", ImVec2(0, 0), ImGuiChildFlags_None, ImGuiWindowFlags_HorizontalScrollbar))
 	{
 		const bool has_filter = filter_[0] != '\0';
-		for (const std::string& line : lines_)
+		for (const Line& line : lines_)
 		{
-			if (has_filter && line.find(filter_) == std::string::npos)
+			if (has_filter && line.text.find(filter_) == std::string::npos)
 			{
 				continue;
 			}
-			ImGui::TextUnformatted(line.c_str());
+			switch (line.level)
+			{
+			case LogLevel_Warn:
+				ImGui::TextColored(ImVec4(1.0f, 0.8f, 0.3f, 1.0f), "%s", line.text.c_str()); // amber
+				break;
+			case LogLevel_Error:
+				ImGui::TextColored(ImVec4(1.0f, 0.45f, 0.4f, 1.0f), "%s", line.text.c_str()); // red
+				break;
+			default:
+				ImGui::TextUnformatted(line.text.c_str());
+				break;
+			}
 		}
 		// Stick to the bottom while new lines arrive (unless the user scrolled up).
 		if (autoscroll_ && ImGui::GetScrollY() >= ImGui::GetScrollMaxY() - 1.0f)

host/src/log_panel.hpp

@@ -25,7 +25,12 @@ public:
 private:
 	void add_line(const LogRecord& rec);
 
-	std::deque<std::string> lines_;
+	struct Line
+	{
+		std::string text;
+		std::uint32_t level; // LogLevel, for colouring
+	};
+	std::deque<Line> lines_;
 	char filter_[96] = {};
 	bool autoscroll_ = true;
 	std::uint64_t first_millis_ = 0; // hook clock at the first line, for relative timestamps