Add VAD segmentation and Docker ENV defaults

bridge/README.md

@@ -7,9 +7,12 @@ It provides:
 - MQTT status/events (`evs/<device_id>/status`)
 - MQTT playback input (`evs/<device_id>/play_pcm16le`)
 - Optional Home Assistant webhook callbacks (`connected`, `start`, `stop`, `disconnected`)
+- VAD auto-segmentation (`vad_segment`) with pre-roll/post-roll
 
 ## 1) Start the bridge
 
+The image already contains sane default `ENV` values. A custom `.env` is optional.
+
 1. Copy env template:
 ```bash
 cp .env.example .env
@@ -58,6 +61,7 @@ Then upload firmware.
 
 - Status/events published by bridge:
   - `evs/<device_id>/status` (JSON)
+  - includes `type: "vad_segment"` when a speech segment is finalized
 - Playback input to device:
   - `evs/<device_id>/play_pcm16le`
   - payload options:
@@ -86,6 +90,13 @@ You can build automations on these events (for STT/TTS pipelines or Node-RED han
   - `WAV_SEGMENT_MAX_BYTES` max size per `.wav` file (default: `20971520` = 20 MB)
   - `WAV_KEEP_FILES` max number of `.wav` files to keep (default: `10`)
 - `MAX_SESSION_BYTES` is only used if session file saving is disabled
+- Voice activity detection (VAD):
+  - `VAD_ENABLED=true` enables automatic speech segment detection
+  - `VAD_PREROLL_MS=1000` keeps 1s before speech start
+  - `VAD_POSTROLL_MS=1000` keeps 1s after speech end
+  - `VAD_START_THRESHOLD` / `VAD_STOP_THRESHOLD` tune sensitivity
+  - `VAD_DIR` stores per-utterance WAV files
+  - `VAD_KEEP_FILES` limits stored VAD WAV files
 - MQTT is recommended for control/events, WebSocket for streaming audio
 
 ## 7) Build and push to Gitea registry
@@ -135,6 +146,14 @@ services:
       PCM_SAMPLE_RATE: "16000"
       WAV_SEGMENT_MAX_BYTES: "20971520"
       WAV_KEEP_FILES: "10"
+      VAD_ENABLED: "true"
+      VAD_DIR: "/data/vad"
+      VAD_KEEP_FILES: "100"
+      VAD_PREROLL_MS: "1000"
+      VAD_POSTROLL_MS: "1000"
+      VAD_START_THRESHOLD: "900"
+      VAD_STOP_THRESHOLD: "600"
+      VAD_MIN_SPEECH_MS: "300"
     volumes:
       - evs_bridge_data:/data