Paginated Topic Sessions in the API (v3.9)

The API and MCP server handle large Topics properly.

GetTopicSessions accepts limit and startAfter, so a Topic with more than 50 sessions can be paged through instead of stopping at the first page.
Topic colours are accepted with or without a leading hash, matching what the app writes and the API returns.
The OpenAPI spec now documents session duration as whole minutes, and iconName as a numeric codepoint.

Requires API access and Hedy Pro.