fix: lower project file format from objectVersion 110 to 77

Xcode Cloud (running a stable, non-beta Xcode) rejected the project
outright: "cannot be opened because it is in a future Xcode project
file format (110)". 110 is whatever the local beta Xcode (this whole
project has been developed against Xcode 27 beta) bumps the format to
on save - not something the project actually needs.

The project itself already had the answer: preferredProjectObjectVersion
= 77 was already present, Xcode's own note that 77 is the actual
minimum format required (it's what introduced fileSystemSynchronizedGroups,
which this project uses - the mechanism that's been letting new source
files just get picked up without explicit PBXFileReference entries all
session). Set objectVersion to match.

Opening/saving this project again in the local beta Xcode will very
likely bump objectVersion back to 110 silently - worth checking this
value before any future push if that happens.

Outpost.xcodeproj/project.pbxproj

@@ -3,7 +3,7 @@
 	archiveVersion = 1;
 	classes = {
 	};
-	objectVersion = 110;
+	objectVersion = 77;
 	objects = {
 
 /* Begin PBXBuildFile section */