feat: add WS Gateway and Chat Service (Step 2)

WS Gateway:
- WebSocket lifecycle handler with RS256 JWT auth
- Redis bridge: device registry, frame publishing, tool_result routing
- Inbound routing: tool_result→LPUSH, home/floating→chat pub/sub
- Outbound: subscribes to ws:out:{user_id}, forwards to Electron
- Single-worker Dockerfile (long-lived WS connections)

Chat Service:
- Redis consumer: subscribes to chat:request:* pattern
- Redis-based ws_context: tool_call→publish, BRPOP tool_result (30s timeout)
- deep_agent: single-agent runner with home/floating/stream variants
- memory_middleware: core/associative/episodic/proactive memory with Fernet
- Domain agents: task (8 tools), note (5), project (6), timeline (4)
- LLM factory via LiteLLM (100+ providers)
- Output formatter (StreamFormatter)
- POST /chat REST fallback with Traefik header auth
- Multi-worker Dockerfile with 120s timeout for LLM calls

services/chat/Dockerfile

@@ -0,0 +1,36 @@
+# ── builder ──────────────────────────────────────────────────────────────────
+FROM python:3.12-slim AS builder
+
+WORKDIR /build
+
+COPY services/chat/requirements.txt ./requirements.txt
+RUN pip install --upgrade pip && \
+    pip install --no-cache-dir --prefix=/install -r requirements.txt
+
+# ── runtime ──────────────────────────────────────────────────────────────────
+FROM python:3.12-slim AS runtime
+
+RUN addgroup --system appgroup && adduser --system --ingroup appgroup appuser
+
+WORKDIR /app
+
+COPY --from=builder /install /usr/local
+
+# Shared module
+COPY shared/ shared/
+
+# Service source
+COPY services/chat/app/ app/
+
+RUN chown -R appuser:appgroup /app
+
+USER appuser
+
+EXPOSE 8000
+
+# Chat service is CPU-bound (LLM calls) — use multiple workers
+CMD ["gunicorn", "app.main:app", \
+     "-k", "uvicorn.workers.UvicornWorker", \
+     "--bind", "0.0.0.0:8000", \
+     "--workers", "2", \
+     "--timeout", "120"]