chore: apply oxlint fix-suggestions (unused imports + useless fragments)

Scoped to only `no-unused-vars` and `react/jsx-no-useless-fragment` —
the safe subset of --fix-suggestions. Primary changes:

- Remove unused named imports from statements
- Remove unused default/type imports entirely
- Collapse `<><Single/></>` fragments to `<Single/>`

Verified clean: typecheck + format + lint all green.

packages/app/e2e/launcher-tab.spec.ts

@@ -17,7 +17,6 @@ import {
 } from "./helpers/launcher";
 import {
   connectTerminalClient,
-  waitForTerminalContent,
   setupDeterministicPrompt,
   type TerminalPerfDaemonClient,
 } from "./helpers/terminal-perf";