feat: initial commit — VoiceCoach real-time voice coaching pipeline

Services: Pipecat agent (LiveKit + Claude + Whisper STT + Piper TTS),
SpeechBrain analysis service, Piper TTS service, web client (nginx).
Includes LiveKit server config and docker-compose orchestration.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

web-client/nginx.conf

@@ -0,0 +1,15 @@
+server {
+    listen 80;
+    root /usr/share/nginx/html;
+    index index.html;
+
+    location /api/ {
+        proxy_pass http://pipecat-agent:8080/;
+        proxy_http_version 1.1;
+        proxy_set_header Host $host;
+    }
+
+    location / {
+        try_files $uri $uri/ /index.html;
+    }
+}