feat: Add environment variable diagnostic script

- Create debug_env_vars.py to check HF environment variable detection
- Helps troubleshoot STT_SERVICE_MODE and TTS_SERVICE_MODE issues
- Shows all environment variables and service mode detection
- Useful for debugging Hugging Face Spaces configuration

🤖 Generated with [Claude Code](https://claude.ai/code)

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

debug_env_vars.py

@@ -0,0 +1,60 @@
+#!/usr/bin/env python3
+"""
+Debug script to check environment variables in Hugging Face Spaces
+"""
+
+import os
+import sys
+
+def check_environment_variables():
+    """Check if environment variables are properly set"""
+    
+    print("🔍 ENVIRONMENT VARIABLE DIAGNOSTIC")
+    print("=" * 50)
+    
+    # Check all environment variables
+    print("📋 All Environment Variables:")
+    env_vars = dict(os.environ)
+    
+    # Look for our specific variables
+    target_vars = ["STT_SERVICE_MODE", "TTS_SERVICE_MODE"]
+    
+    print(f"\n🎯 Target Variables:")
+    for var in target_vars:
+        value = os.environ.get(var, "NOT SET")
+        print(f"  {var} = '{value}'")
+    
+    print(f"\n🔍 All Variables Starting with 'STT' or 'TTS':")
+    for key, value in env_vars.items():
+        if key.startswith(("STT", "TTS")):
+            print(f"  {key} = '{value}'")
+    
+    print(f"\n📊 Total Environment Variables: {len(env_vars)}")
+    
+    # Check common HF environment variables
+    print(f"\n🚀 Hugging Face Environment:")
+    hf_vars = ["SPACE_ID", "SPACE_AUTHOR", "SPACE_REPO", "SPACE_TITLE"]
+    for var in hf_vars:
+        value = os.environ.get(var, "NOT SET")
+        print(f"  {var} = '{value}'")
+    
+    # Test our service mode detection
+    print(f"\n🎛️ Service Mode Detection Test:")
+    stt_mode = os.environ.get("STT_SERVICE_MODE", "websocket").lower()
+    tts_mode = os.environ.get("TTS_SERVICE_MODE", "websocket").lower()
+    
+    print(f"  STT Mode Detected: '{stt_mode}'")
+    print(f"  TTS Mode Detected: '{tts_mode}'")
+    
+    if stt_mode == "websocket":
+        print("  ✅ STT should run in WebSocket mode")
+    else:
+        print("  ❌ STT will NOT run in WebSocket mode")
+        
+    if tts_mode == "websocket":
+        print("  ✅ TTS should run in WebSocket mode")
+    else:
+        print("  ❌ TTS will NOT run in WebSocket mode")
+
+if __name__ == "__main__":
+    check_environment_variables()