Since I am boatless... and sailing my keyboard, this question is fun to think about...

From my interpretation, the finish line, treated as a gate, means "Rule 18.4 does not apply at a gate mark." And that prior to the gybe, windward orange must keep clear of leeward blue, and blue must sail his proper (fastest, shortest) course to the mark. In contrast, if orange could have fetched the committee boat without gybing, he could have demanded room at the mark.

So as drawn, I would side with blue.

http://www.sailing.org/tools/documents/WorldSailingRRS20172020-[20946].pdf
"18.4 Gybing
When an inside overlapped right-of-way boat must gybe at a mark to
sail her proper course, until she gybes she shall sail no farther from
the mark than needed to sail that course. Rule 18.4 does not apply at
a gate mark."

https://www.racingrulesofsailing.org/cases/669?page=5
"W's proper course is not relevant to the application of the rules to this incident. She was required to keep clear of L."

https://www.racingrulesofsailing.org/cases/243?page=16
"Different boats may have different proper courses at any moment depending on the circumstances. However, when those proper courses put the boats on converging courses, the windward boat must keep clear of the leeward boat."