fix: drop Node 18 fallback — path is not in scope before __dirname in bundle

GLM-5 review correctly identified that `path` is defined AFTER `__dirname`
in the bundled output, so the `path.dirname(fileURLToPath(...))` fallback
would throw `ReferenceError` on Node < 20.11.0.

Since Node 18 is EOL (April 2025), use `import.meta.dirname` unconditionally.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: suryaiyer95

packages/dbt-tools/script/copy-python.ts

@@ -22,9 +22,9 @@ const indexPath = join(dist, "index.js")
 let code = readFileSync(indexPath, "utf8")
 const pattern = /var __dirname\s*=\s*"[^"]*python-bridge[^"]*"/
 if (pattern.test(code)) {
-  // Fallback for Node < 20.11.0 where import.meta.dirname is unavailable.
-  // The bundle already imports fileURLToPath from "url", so path + url are in scope.
-  const replacement = `var __dirname = typeof import.meta.dirname === "string" ? import.meta.dirname : path.dirname(fileURLToPath(import.meta.url))`
+  // import.meta.dirname is supported by Bun and Node >= 20.11.0.
+  // Node 18 is EOL (April 2025), so no fallback needed.
+  const replacement = `var __dirname = import.meta.dirname`
   code = code.replace(pattern, replacement)
   writeFileSync(indexPath, code)
   console.log(`Patched __dirname in dist/index.js`)