feat: Phase 1 — ReAct loop + Markdown rendering + Docker deployment

Backend:
- Enterprise Agent refactored from single-round to ReAct multi-turn loop
- New agent.ts (LLM decision node) + tool-executor.ts (tool execution + Gen-UI)
- tool-defs.ts extracted for shared tool schemas
- MAX_ITERATIONS=6 safeguard against infinite loops

Frontend:
- MessageBubble: Markdown + code highlighting + LaTeX + tables
- ThemeToggle: light/dark/system theme cycling
- chart-result Gen-UI card: recharts bar/line/pie/area charts

Infrastructure:
- Docker Compose (lightweight): only LangGraph + Frontend, Azure cloud for PG/Redis/Blob
- Dockerfiles for dev (hot reload) and prod
- Makefile with dev/prod/down/logs commands
- Updated CLAUDE.md and agent definitions for LangGraph.js architecture

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

langgraph/Dockerfile.dev

@@ -0,0 +1,27 @@
+# LangGraph Server - Development
+# Hot reload via source volume mounts (see docker-compose.yml)
+FROM node:20-slim
+
+RUN apt-get update && apt-get install -y curl && rm -rf /var/lib/apt/lists/*
+
+WORKDIR /app
+
+# Install pnpm
+RUN npm install -g pnpm@10
+
+# Copy package files for dependency caching
+COPY package.json pnpm-lock.yaml .npmrc ./
+
+# Install all dependencies (including devDependencies)
+RUN pnpm install --frozen-lockfile
+
+# Copy source code (will be overridden by volume mounts in dev)
+COPY . .
+
+# LangGraph dev prerequisites
+RUN touch .env && mkdir -p .langgraph_api
+
+EXPOSE 2024
+
+# Start LangGraph.js dev server with watch mode
+CMD ["./node_modules/.bin/langgraphjs", "dev", "--host", "0.0.0.0", "--port", "2024", "--no-browser"]