1. Delete braille.go + braille_test.go — dead code, only referenced
by its own test. Can be re-added when latency charts are built.
2. Hoist duplicate `const sparkWidth = 40` (update.go + view_detail.go)
to package-level `detailSparkWidth`. Click-index resolution and
rendering now share one constant.
3. Remove tea.ClearScreen on every resize — caused full-screen flash
during continuous resizes. ctrl+l manual clear kept.