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/.gitattributes

@@ -9,6 +9,9 @@
 # Shell scripts should keep LF
 *.sh text eol=lf
 
+# Archived patch artifacts preserve whitespace exactly
+packages/agent/docs/**/*.diff -whitespace
+
 # Common binary assets
 *.png binary
 *.jpg binary