feat: progress notes UI, search/filter, chat backend relay (HQ-21)

- Add progress note input to TaskDetailPanel (textarea + Cmd+Enter submit)
- Add addProgressNote API function
- Add search bar and priority filter to Queue page
- Include chat backend: WebSocket relay (gateway-relay.ts), chat routes (chat.ts)
- Chat frontend updated to connect via backend relay (/api/chat/ws)

frontend/Dockerfile

@@ -1,11 +1,6 @@
 FROM oven/bun:1 AS build
 WORKDIR /app
 
-ARG VITE_WS_URL=""
-ARG VITE_WS_TOKEN=""
-ENV VITE_WS_URL=$VITE_WS_URL
-ENV VITE_WS_TOKEN=$VITE_WS_TOKEN
-
 COPY package.json bun.lock* ./
 RUN bun install --frozen-lockfile 2>/dev/null || bun install