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/components/modelPicker.tsx

@@ -181,7 +181,10 @@ export function ModelPicker({ gw, onCancel, onSelect, sessionId, t }: ModelPicke
           const idx = off + i
 
           return (
-            <Text color={providerIdx === idx ? t.color.cornsilk : t.color.dim} key={providers[idx]?.slug ?? `row-${idx}`}>
+            <Text
+              color={providerIdx === idx ? t.color.cornsilk : t.color.dim}
+              key={providers[idx]?.slug ?? `row-${idx}`}
+            >
               {providerIdx === idx ? '▸ ' : '  '}
               {i + 1}. {row}
             </Text>
@@ -212,7 +215,10 @@ export function ModelPicker({ gw, onCancel, onSelect, sessionId, t }: ModelPicke
         const idx = off + i
 
         return (
-          <Text color={modelIdx === idx ? t.color.cornsilk : t.color.dim} key={`${provider?.slug ?? 'prov'}:${idx}:${row}`}>
+          <Text
+            color={modelIdx === idx ? t.color.cornsilk : t.color.dim}
+            key={`${provider?.slug ?? 'prov'}:${idx}:${row}`}
+          >
             {modelIdx === idx ? '▸ ' : '  '}
             {i + 1}. {row}
           </Text>