Why

Slack interactions in OpenClaw need a reliable foundation before broader Block Kit expansion. This PR makes interaction routing and payload capture robust while keeping scope Slack-only.

What This PR Adds

• Registers a dedicated Slack interaction event handler in src/slack/monitor/events.ts.
• Implements action handling in src/slack/monitor/events/interactions.ts.
• Adds focused tests in src/slack/monitor/events/interactions.test.ts.

Behavior

• Handles openclaw:* Block Kit interactions.
• Emits structured system events with action metadata (actionId, actionType, selection/date/time values, actor/channel/message IDs).
• Preserves button confirmation UX via row-level replacement.
• Skips message rewrites for non-button interactions.
• Handles modal submissions (view_submission) and emits normalized input summaries.
• Routes session keys correctly for DM/group/channel flows.

Scope

• In scope: Slack monitor interaction plumbing and tests.
• Out of scope: shared cross-channel component abstraction, full Slack renderer expansion, modal close lifecycle follow-ups.

Dependency

Foundation PR for this Slack stack.
Depends on: none.

Validation

• pnpm test src/slack/monitor/events/interactions.test.ts
• pnpm test src/slack/monitor/events/interactions.test.ts src/slack/monitor/slash.test.ts
• pnpm check
• Manual dev verification on Slack dev gateway (18790): button, static select, overflow, datepicker.

Reviewer Focus

• src/slack/monitor/events/interactions.ts
• src/slack/monitor/events/interactions.test.ts
• src/slack/monitor/events.ts