Update detect_package_manager to look for new Bun lockfile

Bun is in the process of switching from the binary `bun.lockb` file to a new, text-based `bun.lock` file. 

As of Bun 1.2, the new text-based lockfile is the default. We need to update the `detect_package_manager` to look for both lockfile formats, but we should be able to eventually retire the binary lockfile format.

More info: https://bun.sh/docs/install/lockfile#text-based-lockfile

vite_ruby/lib/vite_ruby/config.rb

@@ -108,7 +108,7 @@ def coerce_booleans(config, *names)
   def detect_package_manager(root)
     return "npm" if root.join("package-lock.json").exist?
     return "pnpm" if root.join("pnpm-lock.yaml").exist?
-    return "bun" if root.join("bun.lockb").exist?
+    return "bun" if root.join("bun.lockb").exist? || root.join("bun.lock").exist?
     return "yarn" if root.join("yarn.lock").exist?
 
     "npm"