Add web-based AI conference assistant example with chat UI and batch note creation

[Copilot]

Web-based AI chat interface for generating HackMD book-mode conference notes. Users provide API keys from the browser, upload session data, preview generated markdown, then batch-create notes with rate-limit-aware progress tracking.

Architecture

• Next.js 16 + Vercel AI SDK v6 — TextStreamChatTransport for streaming chat, streamText with tool-use on the server
• No server-side secrets — HackMD API key, OpenAI key, and team path all provided from the frontend setup panel
• HackMD API via fetch wrapper (src/lib/hackmd-client.ts) — avoids bundling axios into the serverless runtime

AI Tools (src/lib/tools.ts)

Tool	Purpose
hackmd_get_me	Verify credentials, discover teams
hackmd_get_note	Read existing notes for format reference
hackmd_get_team_notes	List team workspace notes
jq_query	Token-efficient session data analysis (length, keys, group_by, select, map, sort_by, unique, flat_map)
generate_pages	Produce homepage + all session pages for preview

The jq_query tool is key for keeping token usage low — the AI analyzes data shape/counts without ingesting full session JSON into the conversation context.

Batch Note Creation (/api/create-notes)

SSE endpoint that streams progress events as notes are created:

POST /api/create-notes
→ data: {"phase":"creating-sessions","completed":3,"total":49,"current":"Talk Title",...}
→ data: {"phase":"creating-book","completed":48,...}
→ data: {"phase":"done","mainBookUrl":"https://hackmd.io/abc123",...}

• Configurable delay between requests (default 300ms)
• Auto 10s pause on 429 responses
• Failed sessions are omitted from homepage links rather than leaving broken anchors

Frontend Components

• setup-panel — credential entry + team verification
• chat-panel — AI chat with file upload, tool invocation display
• preview-panel — markdown preview with page selector
• progress-modal — real-time creation progress with log output

Root README

Updated to document the new example alongside existing nodejs/ and book-mode-conference/ examples.