Refactor to reduce code duplication in AssignUnassignEventView

Extract joinedAssignees and joinedUnassignees into variables to avoid
repeating the joinWithAnd expressions and improve maintainability.

Co-authored-by: alexr00 <38270282+alexr00@users.noreply.github.com>

Author: Copilot

webviews/components/timeline.tsx

@@ -456,6 +456,8 @@ const AssignUnassignEventView = ({ event }: { event: AssignEvent | UnassignEvent
 	const { actor } = event;
 	const assignees = (event as AssignEvent).assignees || [];
 	const unassignees = (event as UnassignEvent).unassignees || [];
+	const joinedAssignees = joinWithAnd(assignees.map(a => <AuthorLink key={`${a.id}a`} for={a} />));
+	const joinedUnassignees = joinWithAnd(unassignees.map(a => <AuthorLink key={`${a.id}u`} for={a} />));
 
 	// Check if actor is assigning/unassigning themselves
 	const isSelfAssign = assignees.length === 1 && assignees[0].login === actor.login;
@@ -464,13 +466,13 @@ const AssignUnassignEventView = ({ event }: { event: AssignEvent | UnassignEvent
 	let message: JSX.Element;
 	if (assignees.length > 0 && unassignees.length > 0) {
 		// Handle mixed case with potential self-assignment
-		const assignMessage = isSelfAssign ? <>assigned themselves</> : <>assigned {joinWithAnd(assignees.map(a => <AuthorLink key={`${a.id}a`} for={a} />))}</>;
-		const unassignMessage = isSelfUnassign ? <>removed their assignment</> : <>unassigned {joinWithAnd(unassignees.map(a => <AuthorLink key={`${a.id}u`} for={a} />))}</>;
+		const assignMessage = isSelfAssign ? <>assigned themselves</> : <>assigned {joinedAssignees}</>;
+		const unassignMessage = isSelfUnassign ? <>removed their assignment</> : <>unassigned {joinedUnassignees}</>;
 		message = <>{assignMessage} and {unassignMessage}</>;
 	} else if (assignees.length > 0) {
-		message = isSelfAssign ? <>assigned themselves</> : <>assigned {joinWithAnd(assignees.map(a => <AuthorLink key={`${a.id}a`} for={a} />))}</>;
+		message = isSelfAssign ? <>assigned themselves</> : <>assigned {joinedAssignees}</>;
 	} else {
-		message = isSelfUnassign ? <>removed their assignment</> : <>unassigned {joinWithAnd(unassignees.map(a => <AuthorLink key={`${a.id}u`} for={a} />))}</>;
+		message = isSelfUnassign ? <>removed their assignment</> : <>unassigned {joinedUnassignees}</>;
 	}
 
 	return (