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>

common/include/coop/protocol.hpp

@@ -12,7 +12,7 @@ namespace coop
 
 // Bump whenever the layout of SharedBlock or CoopPadState changes. The hook
 // refuses to attach to a host with a mismatched version.
-inline constexpr std::uint32_t kProtocolVersion = 14;
+inline constexpr std::uint32_t kProtocolVersion = 15;
 
 // 'COOP' little-endian, used to sanity-check the mapping before trusting it.
 inline constexpr std::uint32_t kProtocolMagic = 0x504F4F43u;
@@ -60,7 +60,9 @@ enum AudioFormatState : std::uint32_t
 	AudioFormat_Unknown = 0,   // no format determined yet
 	AudioFormat_Exact = 1,     // taken from the game's own IAudioClient::Initialize
 	AudioFormat_Measuring = 2, // guessed (device mix format); true sample rate being measured
-	AudioFormat_Measured = 3,  // guessed rate measured; channels/bits assumed from the device
+	AudioFormat_Measured = 3,  // guessed rate measured (consensus on a standard rate); ch/bits assumed
+	AudioFormat_LowConfidence = 4, // rate never reached consensus; best estimate published -- verify/override
+	AudioFormat_Override = 5,  // operator set this format manually (see the per-stream op channel)
 };
 
 struct AudioStreamInfo