Add browser-based web client

[deepen-pro]

Summary

This PR adds a standalone browser-based web client for OpenHer under web/. The client provides a Vite + React interface for persona discovery, awakening, chat, demo playback, engine status, debugging views, and frontend rendering for backend-generated image and voice replies while keeping the existing Python backend and persona engine unchanged.

Motivation

The project currently focuses on the Python backend and the macOS desktop client. A web client makes OpenHer easier to try across platforms, especially for users who do not have macOS or prefer to interact with the engine from a browser.

Changes

• Add a new web/ Vite + React application.
• Add typed REST and WebSocket clients for the existing OpenHer backend.
• Add browser UI for discovery, awakening, chat, settings, demo controls, engine status, and debug panels.
• Render backend-generated photo replies in the web chat, with accessible zoom preview.
• Render backend-generated voice replies in the web chat through the existing tts_audio WebSocket event.
• Add focused tests for demo state/catalog logic, workspace layout helpers, and web media rendering.
• Document optional web client setup and usage in both Chinese and English READMEs.
• Ignore local IDE metadata with .idea/.

Validation

• npm test
• npm run build