fix: remove hasSelectedAgent gate from Cmd+E and focus mode shortcuts

The hasSelectedAgent condition was redundantly gating Cmd+E (toggle right
sidebar) and Cmd+Shift+F (toggle focus mode) behind a pathname check that
Cmd+B and Cmd+. didn't require. The action handler already guards against
invalid states, making the when-clause check unnecessary and broken on the
dev branch's navigation flow.

packages/app/src/keyboard/keyboard-shortcuts.test.ts

@@ -29,7 +29,6 @@ function shortcutContext(
     isDesktop: false,
     focusScope: "other",
     commandCenterOpen: false,
-    hasSelectedAgent: true,
     ...overrides,
   };
 }