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>

livekit/livekit.yaml

@@ -0,0 +1,15 @@
+port: 7880
+rtc:
+  tcp_port: 7881
+  port_range_start: 50000
+  port_range_end: 60000
+  use_external_ip: true
+
+logging:
+  json: false
+  level: info
+
+room:
+  max_participants: 5
+  empty_timeout: 300
+  departure_timeout: 30