Reject duplicate resolved paths in apply_patch (#37867)

## What changed

- Reject patches containing multiple operations whose paths resolve to the same file, such as `duplicate.txt` and `./duplicate.txt`.
- Preserve support for patches that update multiple distinct files.

## Testing

- Add CLI integration coverage for distinct updates and duplicate resolved paths.

GitOrigin-RevId: 0fb7f69ae31acc5c677268ffd9e38ad8d8314276

codex-rs/apply-patch/src/invocation.rs

@@ -232,6 +232,13 @@ async fn try_verify_apply_patch_args(
     let mut changes = HashMap::new();
     for hunk in hunks {
         let path = hunk.resolve_path(&effective_cwd)?;
+        if changes.contains_key(&path) {
+            return Err(ParseError::InvalidPatchError(format!(
+                "multiple operations target {}",
+                path.inferred_native_path_string()
+            ))
+            .into());
+        }
         match hunk {
             Hunk::AddFile { contents, .. } => {
                 changes.insert(path, ApplyPatchFileChange::Add { content: contents });