perf: Reduce AI TUI rendering overhead for long conversations (#3447)

Fixes keystroke lag in Atuin AI that scales with conversation length.
After extended use (many turns, lots of tool calls with output
viewports), pressing a key had noticeable delay before the letter
appeared.

Three layers of optimization:

- **Skip `sync_view_state` for `InputUpdated`** — every keystroke was
cloning all events, tools, and archived data even though no FSM state
changed. Uses `handle.update_tracked()` (eye_declare 0.5) to skip
rebuilds when values haven't actually changed.

- **Pre-compute turns and `has_command` on the driver thread** — the
view function was rebuilding the full turn structure from raw events and
scanning for `suggest_command` tool calls 3× per render frame. Now
computed once per FSM state change and cached in ViewState.

- **Commit-based element tree pruning** — turns that scroll into
terminal scrollback are tracked via `on_commit` and filtered from the
element tree, keeping rendering work proportional to visible content.
Turn views are now direct children of the root VStack (not nested inside
AtuinAi) so `detect_committed` can see them.

0 files changed, 0 insertions, 0 deletions