Add AgentCore Browser Tool Support

## Summary

Add Amazon Bedrock AgentCore Browser support to FAST, enabling AI agents to autonomously browse the web with real-time live view streaming for end users. This includes new agent patterns, a browser tool integration, and frontend tool rendering for the browser live view.

## Scope

### 1. Agent Patterns

**Multi-agent pattern:**
- Strands agent with browser-use library + Claude for autonomous browser control
- Includes all the existing Gateway MCP tools and Code Interpreter, and the new Browser tool

**Single-agent patterns:**
- `strands-browser-agent` — Strands SDK with browser tool only
- `novaAct-browser-agent` — NovaAct SDK with browser tool
- `browserUse-agent` — BrowserUse SDK with browser tool

### 3. Frontend: Tool Rendering

**`BrowserToolDisplay.tsx`** — Custom tool renderer registered for `name === "browser"`:
- Expandable view showing: Input (task + URL) → Browser actions → Result
- Real-time streaming of browser actions during execution
- Embedded DCV live view via `BrowserLiveView` component (memoized to prevent reconnections)

**`BrowserLiveView.tsx`** — Wrapper around `bedrock-agentcore` npm package:
- Uses official `BrowserLiveView` component from `bedrock-agentcore/browser/live-view`