fix(cmd-j): give the tab-results mock entries their occupant agent

Same class as #15207: a required field was added to SearchableWorkspaceTab
without updating this hoisted mock, so main fails typecheck and the tab-bar
suite.

src/renderer/src/components/tab-bar/TabBarCreateEntry.tab-results.test.tsx

@@ -78,6 +78,7 @@ const tabSearchMock = vi.hoisted(() => {
               branch: 'main',
               repoName: 'octo/rocket'
             }),
+            occupantAgent: null,
             agentMetadata: [],
             isCurrentTab: false,
             isCurrentWorktree: true