chore(tui): /clean recent perf work — KISS/DRY pass

24 files, -319 LoC. Behaviour preserved, 369/369 tests green.

- hermes-ink caches: shared lruEvict helper for the four parallel LRU
  caches (stringWidth, wrapText, sliceAnsi, lineWidth); touch-on-read
  stays inlined per cache; tightened output.ts skip-slice fast path.
- wheelAccel: trimmed provenance header, collapsed env parsing, ternary
  dispatch in computeWheelStep.
- perfPane: folded ensureLogDir into once-flag, spread-with-overrides
  for fastPath/phases instead of full rebuilds.
- env: extracted truthy() (used 4×).
- virtualHeights: collapsed user/diff/slash height bumps; trail+todos
  estimate.
- useInputHandlers: scrollIdleTimer cleanup on unmount, ?? undefined
  shorthand.
- useMainApp: dropped dead liveTailVisible IIFE and liveProgress
  indirection.
- appLayout, markdown, messageLine, entry: vertical rhythm, dropped
  narration comments, inlined one-shot vars.
- fix: empty catch blocks → /* best-effort */ for no-empty lint.

ui-tui/src/lib/liveProgress.ts

@@ -38,8 +38,7 @@ const isBarrierMessage = (msg: Msg | undefined) => {
   return false
 }
 
-const isToolCarryingTrail = (msg: Msg | undefined) =>
-  Boolean(msg?.kind === 'trail' && !msg.text && msg.tools?.length)
+const isToolCarryingTrail = (msg: Msg | undefined) => Boolean(msg?.kind === 'trail' && !msg.text && msg.tools?.length)
 
 export const appendToolShelfMessage = (prev: readonly Msg[], msg: Msg): Msg[] => {
   if (!isToolShelfMessage(msg)) {