Fix Intercom types for conversation_part.tag.* events

[Macil]

No description provided.

[greptile-apps]

Greptile Summary

This PR fixes TypeScript type inference for Intercom webhook events whose topics have two dots (e.g. conversation_part.tag.added, conversation_part.tag.removed). Previously the topic-to-payload mapping only handled single-prefix topics (<type>.<action>), causing these three-part topics to resolve to unknown. The fix introduces a IntercomWebhookSubtopicTypeMap keyed on two-part prefixes ("conversation_part.tag"), reworks IntercomWebhookPrefix<T> to try the longer two-part match first, and adds IntercomWebhookPayload<TMap, TPrefix> to safely narrow the type field. A new public IntercomConversationPartTag interface describes the payload shape (wrapping Conversation + Tag objects), and a companion type-test file verifies both the single-topic and mixed-topic narrowing paths.

Confidence Score: 5/5

• Safe to merge — pure TypeScript type change with no runtime behaviour affected and comprehensive type-level tests.
• All changes are compile-time only. The type inference logic is correct: IntercomWebhookPrefix correctly matches the longest valid prefix (two-part before one-part), IntercomWebhookPayload safely narrows the type field without breaking existing, more-specific types, and the new IntercomConversationPartTag interface is well-formed with the correct literal type. Tests cover the four key paths (single new-topic, single old-topic, mixed new+old, IntercomEvent direct usage). No P0/P1 findings.
• No files require special attention.

Important Files Changed

Filename	Overview
integrations/intercom/runtime.ts	Adds IntercomConversationPartTag interface and reworks the webhook item type inference to support 3-part topics (e.g. conversation_part.tag.added) via a new IntercomWebhookSubtopicTypeMap and helper types IntercomWebhookPrefix, IntercomWebhookPayload, and IntercomWebhookItem.
integrations/intercom/runtime.types.test.ts	Adds type-level tests for conversation_part.tag.added (single and mixed-event listener), verifies type narrowing for existing event types like contact, conversation, job, and ticket.
mod.ts	Exports the new IntercomConversationPartTag type from the public API surface.

_{Reviews (1): Last reviewed commit: "update intercom docs link" | Re-trigger Greptile}

[gemini-code-assist]

Code Review

This pull request improves the type inference for Intercom webhook events by introducing a more sophisticated mapping system. It adds support for subtopics (e.g., 'conversation_part.tag'), ensures the 'type' property on event payloads is correctly narrowed, and includes the new IntercomConversationPartTag interface. The changes are accompanied by updated type tests and exports. I have no feedback to provide.