Initial commit: bt411 -- standalone Windows BattleTech (Tesla 4.10 port)

Clean, self-contained extraction of the BattleTech-specific work from the
reverse-engineering workspace -- engine + game + content + build, with nothing
from Red Planet or the raw archive dumps. Builds green (Win32) and runs the
single-player drive->animate->target->fire->damage->destroy loop out of the box.

Layout:
  engine/   MUNGA + MUNGA_L4 shared 2007 engine, carrying our BT render/loader
            work (bgfload/L4D3D/L4VIDEO: BSL bit-slice decode, LOD/ground/shadow
            models) + image codec; the minimal rp/ headers the audio HAL needs
  game/     reconstructed BT logic + surviving-original BT source + fwd shims
            + WinMain launcher
  content/  full runtime tree (BTL4.RES, VIDEO/, GAUGE/, AUDIO/, eggs, BTDPL.INI)
  docs/     format specs + reconstruction ledgers
  reference/ raw Ghidra pseudocode (recon source-of-truth) + decomp exporter
  tools/    MP console emulator + map/resource scanners

One top-level CMake builds munga_engine lib + bt410_l4 game lib + btl4.exe.
All paths relativized (186 fwd shims + ~437 CMake abs paths -> repo-relative);
DXSDK is the one external, overridable via -DDXSDK. Verified: builds to a
byte-identical 2.27MB exe and runs combat (TARGET DESTROYED, 0 crashes) against
the bundled content.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

content/AUDIO/AUDIO.INI

@@ -0,0 +1,53 @@
+[AudioRenderer]
+
+#
+# Radius of clipping sphere
+#
+clipping_radius=450.0
+
+#
+# Distance between ears 
+#
+distance_between_ears=2.0
+
+#
+# Control amplitude rolloff
+#
+amplitude_rolloff=2.0
+amplitude_rolloff_knee=60.0
+amplitude_rolloff_distance_scale=0.003
+
+#
+# Control high frequency rolloff
+#
+high_frequency_rolloff=2.0
+high_frequency_rolloff_knee=60.0
+high_frequency_rolloff_distance_scale=0.0035
+
+#
+# Control doppler
+#
+doppler_range=600.0
+speed_of_sound=250.0
+
+#
+# Control source compression
+#
+compression_scale=0.92
+compression_exponent=8.5
+
+#
+# ITD difference constant
+#
+itd_difference=0.0015
+
+#
+# Global reverb scale
+#
+global_reverb_scale=0.3
+
+[AudioResources]
+front_audio_resource=audio\audio1.res
+front_audio_resource=audio\audio2.res
+rear_audio_resource=audio\audio1.res
+rear_audio_resource=audio\audio2.res

content/AUDIO/AUDIOMR.INI

@@ -0,0 +1,53 @@
+[AudioRenderer]
+
+#
+# Radius of clipping sphere
+#
+clipping_radius=700.0
+
+#
+# Distance between ears 
+#
+distance_between_ears=2.0
+
+#
+# Control amplitude rolloff
+#
+amplitude_rolloff=2.0
+amplitude_rolloff_knee=60.0
+amplitude_rolloff_distance_scale=0.002
+
+#
+# Control high frequency rolloff
+#
+high_frequency_rolloff=2.0
+high_frequency_rolloff_knee=60.0
+high_frequency_rolloff_distance_scale=0.003
+
+#
+# Control doppler
+#
+doppler_range=600.0
+speed_of_sound=250.0
+
+#
+# Control source compression
+#
+compression_scale=0.1
+compression_exponent=9.0
+
+#
+# ITD difference constant
+#
+itd_difference=0.0015
+
+#
+# Global reverb scale
+#
+global_reverb_scale=0.3
+
+[AudioResources]
+front_audio_resource=audio\audio1.res
+front_audio_resource=audio\audio2.res
+rear_audio_resource=audio\audio1.res
+rear_audio_resource=audio\audio2.res

content/AUDIO/CTMIX.CFG

@@ -0,0 +1,15 @@
+/MA:229;0
+/VO:0;0
+/MI:229;0
+/CD:0;0
+/LI:0;0
+/MIC:0
+/SP:0
+/TR:114;0
+/BA:114;0
+/IPL:MIC- CDR- CDL- LIR- LIL- MIR- MIL- 
+/IPR:MIC- CDR- CDL- LIR- LIL- MIR- MIL- 
+/OPS:MIC- CDR- CDL- LIR- LIL- 
+/AGC:-
+/IPG:1,1
+/OPG:1,1

content/AUDIO/ICOM.CFG

@@ -0,0 +1,15 @@
+/MA:229;0
+/VO:0;0
+/MI:229;0
+/CD:0;0
+/LI:0;0
+/MIC:0
+/SP:0
+/TR:114;0
+/BA:114;0
+/IPL:MIC- CDR- CDL- LIR- LIL+ MIR- MIL- 
+/IPR:MIC- CDR- CDL- LIR+ LIL- MIR- MIL- 
+/OPS:MIC- CDR- CDL- LIR+ LIL+ 
+/AGC:-
+/IPG:1,1
+/OPG:1,1