chore(vendor): import pi 1.3.0

Imported as a linear vendor commit so forge rebases do not replay the upstream root tree.

git-subtree-dir: third_party/pi

git-subtree-split: 71023aec1546d6d677a65669c5665c0927ce0dd0

third_party/pi/packages/tui/test/viewport-overwrite-repro.ts

@@ -2,11 +2,11 @@
  * TUI viewport overwrite repro
  *
  * Place this file at: packages/tui/test/viewport-overwrite-repro.ts
- * Run from repo root: npx tsx packages/tui/test/viewport-overwrite-repro.ts
+ * Run from repo root: node packages/tui/test/viewport-overwrite-repro.ts
  *
  * For reliable repro, run in a small terminal (8-12 rows) or a tmux session:
  *   tmux new-session -d -s tui-bug -x 80 -y 12
- *   tmux send-keys -t tui-bug "npx tsx packages/tui/test/viewport-overwrite-repro.ts" Enter
+ *   tmux send-keys -t tui-bug "node packages/tui/test/viewport-overwrite-repro.ts" Enter
  *   tmux attach -t tui-bug
  *
  * Expected behavior: