docs: add Frontend section to README (v0.6.0 web workspace)

Overview

The v0.6.0 release introduced the new web workspace (React + TypeScript frontend).
However, the main README.md does not currently document how to launch or use the web interface.

This issue proposes adding a concise ## Frontend section to reflect the current capabilities of the project and improve onboarding.

Release:
https://github.com/aden-hive/hive/releases/tag/v0.6.0

Rationale

• The web UI is now a primary interface for interacting with agents.
• hive serve is not currently documented in the main README.
• New users may default to the TUI without realizing a browser-based workspace exists.
• The README should reflect the current project architecture post-v0.6.0.

Proposed Addition

Add the following section to README.md (placement: after core usage or installation section, aligned with existing structure):

Frontend

Hive includes a modern web interface built with React and TypeScript for agent management and monitoring.

Launch the UI

# Launch the web interface (recommended)
hive serve

# Or start the development server directly
cd core/frontend
npm install
npm run dev

Features

• Agent Management – Browse, create, and configure agents
• Real-time Monitoring – Live execution tracking and logs
• Interactive Chat – Direct communication with running agents
• Graph Visualization – Visual representation of agent workflows

Acceptance Criteria

• README.md includes a ## Frontend section
• Launch instructions are verified against current CLI behavior
• Section placement aligns with existing README structure
• Formatting matches project documentation standards

@bryanadenhq @RichardTang-Aden If there are preferred wording conventions or structural adjustments, I’m happy to align before opening a PR.