Refactor matchActivity to always return the dereferenced activity

Instead of returning the dereferenced activity or `false`, return an array with the success status (`true` or `false`) first, and the dereferenced activity next.

This will allow to optimise requests so that, even if the match fais, we don't need to lose dereferenced data.

Start by locating matchActivity and its callers in the TypeScript codebase, then inspect any tests covering its current return value. Done means the function always returns an array with the success status first and the dereferenced activity second, including when matching fails, with callers and tests aligned to that shape.

Written by the indexing model from the issue text.