Mock sample: Slack API

[waldekmastykarz]

Description

Create a mock sample for the Slack API.

Why

• Massive bot/app developer ecosystem
• Event simulation and webhook testing is challenging
• Modal interactions and message threading are complex to test
• Enables rapid bot development without live workspace

Suggested endpoints to mock

• Web API (chat.postMessage, users.list, channels.list)
• Events API (message events, reactions, mentions)
• Interactive components (modals, buttons, menus)
• OAuth flow responses
• Slash command handling