New terminal UI

A ground-up rebuild of the interactive TUI. Output uses your terminal's native scrollback — scroll freely, click links, select text — no more fixed viewport. Also adds inline search with /.

The old framework (Bubbletea) has been replaced with a new rendering engine built on Tuist, a TUI framework designed for infinite scrollback. Each span in the trace tree is an independent component with its own render cache — only components whose data changed get repainted, using line-level diffs to minimize terminal I/O. The result: a TUI that feels like normal terminal output, but with the rich structure of a trace viewer. Mouse input is no longer captured, so scrolling always works.