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>

tests/CMakeLists.txt

@@ -30,6 +30,12 @@ add_executable(audio_mix_test audio_mix_test.cpp)
 target_include_directories(audio_mix_test PRIVATE ${CMAKE_SOURCE_DIR}/host/src)
 add_test(NAME audio_mix_test COMMAND audio_mix_test)
 
+# Unit test for the robust sample-rate estimator (consensus / reject-non-standard /
+# low-confidence). Pure header logic fed synthetic adversarial cadences. No device.
+add_executable(rate_estimator_test rate_estimator_test.cpp)
+target_include_directories(rate_estimator_test PRIVATE ${CMAKE_SOURCE_DIR}/hook/src)
+add_test(NAME rate_estimator_test COMMAND rate_estimator_test)
+
 # Unit test for the host->game mouse coordinate mapping (letterbox inverse +
 # decorated-window client offset). Header-only, no device.
 add_executable(mkb_map_test mkb_map_test.cpp)
@@ -156,6 +162,7 @@ coop_output_subdir(tests
 	mkb_ring_test
 	mkb_map_test
 	audio_mix_test
+	rate_estimator_test
 	audio_loopback_test
 	audio_hook_test
 	srgb_format_test