Slack plugin support

[ewega]

Summary

Add Slack as a supported DevOps tool in the CLI. Slack is the dominant workplace messaging platform, and its DevLake plugin collects channel message data useful for measuring communication patterns, incident response coordination, and team collaboration metrics.

Upstream Plugin

slack in incubator-devlake/backend/plugins/slack/

Property	Value
Plugin slug	slack
Auth	AccessToken (OAuth access token)
Scope type	Channels (SlackChannel)
Scope ID field	id
Default endpoint	https://open.slack.cn/open-apis/
Remote-scope API	Yes — lists and searches channels with cursor-based pagination
Connection test	Yes

Dependencies

Blocked by:

• Generic scope ID extraction and remote-scope API client #86 — Scope ID extraction (needs ScopeIDField)

Not blocked by #85 — Slack uses AccessToken, compatible with current auth model.

Changes

• Add ConnectionDef for slack in connectionRegistry:
  • Endpoint: "https://open.slack.cn/open-apis/"
  • SupportsTest: true
  • TokenPrompt: "Slack Bot/User OAuth token"
  • EnvVarNames: []string{"SLACK_TOKEN", "SLACK_BOT_TOKEN"}
  • EnvFileKeys: []string{"SLACK_TOKEN", "SLACK_BOT_TOKEN"}
  • ScopeIDField: "id"
  • ScopeFunc: scopeSlackHandler
• Implement scopeSlackHandler:
  • Use client.ListRemoteScopes("slack", connID, "", "") to list channels
  • Use client.SearchRemoteScopes("slack", connID, search, ...) for search
  • Let user select channels interactively
  • PUT selected channels as scopes
• Set Available: true

Acceptance Criteria

• gh devlake configure connection add --plugin slack creates a Slack connection
• Slack appears in interactive plugin picker
• Slack scopes list channels for selection
• Connection test works
• go build ./..., go test ./..., go vet ./... pass