chore(vendor): import pi 0.85.1

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: d981de1229ef899957bbe968bc8dcda02a21f477

third_party/pi/packages/coding-agent/src/utils/json.ts

@@ -0,0 +1,6 @@
+/** Strip `//` line comments and trailing commas from JSON, leaving string literals untouched. */
+export function stripJsonComments(input: string): string {
+	return input
+		.replace(/"(?:\\.|[^"\\])*"|\/\/[^\n]*/g, (m) => (m[0] === '"' ? m : ""))
+		.replace(/"(?:\\.|[^"\\])*"|,(\s*[}\]])/g, (m, tail) => tail ?? (m[0] === '"' ? m : ""));
+}