Merge pull request #30005 from lrycro:fix/glob-readdir-leak

core: fix memory leak in glob()'s readdir() on WinRT/_WIN32_WCE - #30005

## Problem

Fixes #30004

In `modules/core/src/glob.cpp`, the WinRT/`_WIN32_WCE` implementation of `readdir()` allocates a new buffer for `dir->ent.d_name` on every call and overwrites the previous pointer without freeing it:

```cpp
char* aname = new char[asize+1];
...
dir->ent.d_name = aname;
```

`cv::glob()` calls `readdir()` once per directory entry, so every call except the last leaks its allocation. Additionally, the `DIR` destructor that releases `d_name` was gated by `#ifdef WINRT` only, so `_WIN32_WCE` builds leaked every allocation, including the last one.

## Fix

- Free the previous `dir->ent.d_name` before overwriting it in `readdir()`, matching how `~DIR()` already frees it on WinRT.
- Extend the `DIR` destructor guard from `#ifdef WINRT` to `#if defined(WINRT) || defined(_WIN32_WCE)` so the final buffer is also released under `_WIN32_WCE`.

## Checklist

- [x] I agree to contribute to the project under the Apache 2 License.
- [x] To the best of my knowledge, the proposed patch is not based on code under GPL or another license incompatible with OpenCV.
- [x] The PR is proposed to the proper branch (`4.x`).
- [x] There is a reference to the original bug report and related work.
- [ ] There is accuracy test, performance test and test data in opencv_extra repository, if applicable.
- [x] The feature is well documented and sample code can be built with the project CMake.

Thanks for reviewing.

modules/core/src/glob.cpp

@@ -66,7 +66,7 @@ namespace
 #endif
         HANDLE handle;
         dirent ent;
-#ifdef WINRT
+#if defined(WINRT) || defined(_WIN32_WCE)
         DIR() { }
         ~DIR()
         {
@@ -113,6 +113,7 @@ namespace
         char* aname = new char[asize+1];
         aname[asize] = 0;
         wcstombs(aname, dir->data.cFileName, asize);
+        delete[] dir->ent.d_name;
         dir->ent.d_name = aname;
 #else
         if (dir->ent.d_name != 0)