Disable assertions in ALSA static library build

Production builds should not include debug assertions. ALSA's assert()
calls cause aborts when internal invariants are violated, even for
recoverable error conditions.

The crash occurred when snd_pcm_close() was called with a NULL pointer,
triggering assertion failure at pcm.c:779 instead of graceful error
handling.

Stack trace:
  pcm.c:779: snd_pcm_close: Assertion `pcm' failed
  SIGABRT in jetkvm_audio_capture_init()

Adding -DNDEBUG disables all assert() calls in ALSA, Opus, and SpeexDSP
libraries for production robustness.

Author: pennycoders

.devcontainer/install_audio_deps.sh

@@ -38,7 +38,7 @@ cd "$AUDIO_LIBS_DIR"
 [ -d speexdsp-${SPEEXDSP_VERSION} ] || tar xf speexdsp-${SPEEXDSP_VERSION}.tar.gz
 
 # ARM Cortex-A7 optimization flags with NEON support
-OPTIM_CFLAGS="-O2 -mfpu=neon -mtune=cortex-a7 -mfloat-abi=hard"
+OPTIM_CFLAGS="-O2 -mfpu=neon -mtune=cortex-a7 -mfloat-abi=hard -DNDEBUG"
 
 export CC="${CROSS_PREFIX}-gcc"
 export CFLAGS="$OPTIM_CFLAGS"