Dockerize: one-command stack with auto Ollama model pull

`docker compose up -d --build` now brings up the whole thing automatically —
no host setup needed:

- All-in-one javis image: TigerVNC+XFCE desktop, Chrome, Python brain bridge,
  Node/bun bot, managed by supervisord (verified: all 6 programs RUNNING).
- ollama service + one-shot ollama-init that auto-pulls chat+embed models
  (verified end-to-end; `ollama list` shows pulled models).
- Discord token deferred: without DISCORD_BOT_TOKEN the desktop, bridge,
  Ollama and models all run; only the bot waits (no crash loop).
- Slim container deps (bridge/requirements-bridge.txt) drop the unused
  PyQt6/torch/chatterbox/sounddevice stack. Piper voice + Whisper models
  auto-download into named volumes.
- Configurable host ports (VNC_PORT/NOVNC_PORT/BRIDGE_PORT) to avoid clashing
  with a host VNC already on 5901. Bridge binds 0.0.0.0 in-container.

Verified: image builds; brain imports; bridge /health 200; noVNC 200;
X display :1 @1920x1080; auto-pull completes; supervisorctl status all RUNNING.

docker/download-piper.sh

@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+# Download the default Piper voice model if it is not already present.
+# Used both at image build time and (as a fallback) at container start.
+set -euo pipefail
+
+VOICE="${PIPER_VOICE:-en_GB-alan-medium}"
+DEST_DIR="${PIPER_VOICE_DIR:-/opt/piper-voices}"
+BASE="https://huggingface.co/rhasspy/piper-voices/resolve/v1.0.0"
+
+# en_GB-alan-medium -> en/en_GB/alan/medium
+lang2="${VOICE%%-*}"          # en_GB
+lang1="${lang2%%_*}"          # en
+rest="${VOICE#*-}"            # alan-medium
+name="${rest%%-*}"            # alan
+quality="${rest#*-}"          # medium
+path="${lang1}/${lang2}/${name}/${quality}"
+
+mkdir -p "$DEST_DIR"
+onnx="$DEST_DIR/${VOICE}.onnx"
+json="$DEST_DIR/${VOICE}.onnx.json"
+
+if [ -f "$onnx" ] && [ -f "$json" ]; then
+  echo "[piper] voice already present: $onnx"
+  exit 0
+fi
+
+echo "[piper] downloading voice $VOICE ..."
+wget -q -O "$onnx" "${BASE}/${path}/${VOICE}.onnx"
+wget -q -O "$json" "${BASE}/${path}/${VOICE}.onnx.json"
+echo "[piper] saved to $onnx"