docs: Add Meeting Calendar information for Interest and Working Groups

Author: olaservo

docs/community/working-interest-groups.mdx

@@ -22,6 +22,12 @@ These groups exist to:
 
 ## Mechanisms
 
+## Meeting Calendar
+
+All Interest Group and Working Group meetings are published on the public MCP community calendar at [mcp.meetable.org](https://mcp.meetable.org/).
+
+Facilitators are responsible for posting their meeting schedules to this calendar in advance to ensure discoverability and enable broader community participation.
+
 ### Interest Groups (IGs)
 
 **Goal:** Facilitate discussion and knowledge-sharing among MCP contributors who share interests in a specific MCP sub-topic or context. The primary focus is on identifying and gathering problems that may be worth addressing through SEPs or other community artifacts, while encouraging open exploration of protocol issues and opportunities.
@@ -30,6 +36,7 @@ These groups exist to:
 
 - Regular conversations in the Interest Group Discord channel
 - **AND/OR** a recurring live meeting regularly attended by Interest Group members
+- Meeting dates and times published in advance on the [MCP community calendar](https://mcp.meetable.org/)
 
 **Examples**:
 
@@ -68,6 +75,7 @@ Participation in an Interest Group (IG) is not required to start a Working Group
 
 - Meaningful progress towards at least one SEP or spec-related implementation **OR** hold maintenance responsibilities for a project (e.g., Inspector, Registry, SDKs)
 - Facilitators are responsible for keeping track of progress and communicating status when appropriate
+- Meeting dates and times published in advance on the [MCP community calendar](https://mcp.meetable.org/) when applicable
 
 **Examples**: