feat: expose avatar parameter in send_message tool

[Zernio-Elean]

Summary

Expose avatar as an optional parameter in the send_message MCP tool so messages can be sent with the operator's real profile photo.

The Crisp REST API and the internal crisp-client.ts already support user.avatar in SendMessageOptions, but the tool schema didn't expose it. This wires it up.

Changes

src/index.ts (+9, -1):

1. Tool schema: Added avatar as optional string property in send_message inputSchema
2. Tool handler: Reads avatar from args and passes it in the user object to crispClient.sendMessage()

No changes needed in crisp-client.ts since SendMessageOptions already supports user.avatar.

Usage

// 1. Get operator avatar URL
get_operators() // returns list with avatar URLs per operator

// 2. Send message with operator identity
send_message({
  session_id: "...",
  content: "Hello!",
  nickname: "Elean",
  avatar: "https://storage.crisp.chat/users/avatar/operator/.../photo.png"
})

Test plan

• Tested locally with a real Crisp conversation
• Message displays with correct operator photo and name in Crisp UI
• Build passes (npm run build)