Integration: Implement Slack App OAuth2 Connection Flow and Block Kit Notification Engine

[EDOHWARES]

Description

Replace incoming webhook integrations with a full Slack App OAuth2 flow and Block Kit templates.

Current Problem

Webhook integration requires manual channel configuration by the user and is limited to unformatted text notifications.

Proposed Solution

Build a Slack App integration that handles workspaces authentication and builds custom Block Kit notification layouts.

Technical Tasks

• Create Slack OAuth redirect endpoints to retrieve and save workspace access keys
• Implement a Slack notification service mapping payloads to Block Kit components
• Add UI selection for target Slack channels in the trigger configurations page
• Write error handling modules for invalid webhook tokens

Acceptance Criteria

• Users can click an "Add to Slack" button, authorize the app, and select target channels
• Trigger alerts are delivered as formatted Block Kit cards containing event details
• Workspace connection is revocable from the integrations page

Testing Requirements

• Test Slack message generation with local mock endpoints and verify card formatting

Metadata

• Priority: Medium
• Difficulty: Medium