chore(tui): /clean pass — inline one-off locals, tighten ConfirmPrompt

- providers.ts: drop the `dup` intermediate, fold the ternary inline
- paths.ts (fmtCwdBranch): inline `b` into the `tag` template
- prompts.tsx (ConfirmPrompt): hoist a single `lower = ch.toLowerCase()`,
  collapse the three early-return branches into two, drop the
  redundant bounds checks on arrow-key handlers (setSel is idempotent
  at 0/1), inline the `confirmLabel`/`cancelLabel` defaults at the
  use site
- modelPicker.tsx / config/env.ts / providers.test.ts: auto-formatter
  reflows picked up by `npm run fix`
- useInputHandlers.ts: drop the stray blank line that was tripping
  perfectionist/sort-imports (pre-existing lint error)

ui-tui/src/app/useInputHandlers.ts

@@ -7,7 +7,6 @@ import type {
   SudoRespondResponse,
   VoiceRecordResponse
 } from '../gatewayTypes.js'
-
 import { writeOsc52Clipboard } from '../lib/osc52.js'
 
 import { getInputSelection } from './inputSelectionStore.js'