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/pi-test.ps1

@@ -58,13 +58,10 @@ if ($noEnv) {
 	Write-Host "Running without API keys..."
 }
 
-$tsxBin = Join-Path $scriptDir "node_modules/.bin/tsx.cmd"
-if (-not (Test-Path -LiteralPath $tsxBin)) {
-	throw "tsx not found at $tsxBin. Run npm install from the repo root first."
-}
-
+# --import takes a module specifier, so pass the resolver as a file URL (Windows paths are not specifiers).
+$resolverUrl = ([System.Uri](Join-Path $scriptDir "packages/coding-agent/src/experimental/source-resolver.ts")).AbsoluteUri
 $cliPath = Join-Path $scriptDir "packages/coding-agent/src/cli.ts"
-& $tsxBin $cliPath @forwardArgs
+& node --import $resolverUrl $cliPath @forwardArgs
 $exitCode = $LASTEXITCODE
 if ($exitCode -ne 0) {
 	exit $exitCode