fix(installer): prevent destructive PATH overwrite on registry read error

Replace unwrap_or_default() with explicit error matching: only treat
ERROR_FILE_NOT_FOUND as empty PATH (fresh user with no custom PATH).
Any other error (corrupt data, wrong type, permission issue) is now
propagated, preventing the installer from silently replacing the
user's entire PATH with just the vp bin directory.

Author: fengmk2

crates/vite_installer/src/windows_path.rs

@@ -48,7 +48,13 @@ pub fn add_to_user_path(bin_dir: &str) -> io::Result<()> {
     let hkcu = RegKey::predef(HKEY_CURRENT_USER);
     let env = hkcu.open_subkey_with_flags("Environment", KEY_READ | KEY_WRITE)?;
 
-    let current: String = env.get_value("Path").unwrap_or_default();
+    // Only treat "value not found" as empty PATH. Any other error (corrupt
+    // data, wrong type) must be propagated to avoid overwriting the user's PATH.
+    let current: String = match env.get_value("Path") {
+        Ok(val) => val,
+        Err(e) if e.raw_os_error() == Some(2) => String::new(), // ERROR_FILE_NOT_FOUND
+        Err(e) => return Err(e),
+    };
     let bin_dir_normalized = bin_dir.trim_end_matches('\\');
 
     let already_present = current