[firebase_core] Windows Debug crash in App::RegisterLibrary (access violation writing 0x0) before Firebase.initializeApp

### Is there an existing issue for this?

- [x] I have searched the existing issues.

### Which plugins are affected?

Core

### Which platforms are affected?

Windows

### Description

On `Windows Debug`, a Flutter app that depends on `firebase_core` crashes immediately after a successful native build, before the window appears and before Dart can call `Firebase.initializeApp(`).

**Flutter reports:**

`Error waiting for a debug connection: The log reader stopped unexpectedly, or never started.`

Windows Event Viewer records `0xC0000005` (access violation) on the app executable.

A Visual Studio debugger break shows the crash inside Firebase C++ `LibraryRegistry::RegisterLibrary`, while writing `'\0'` through `std::string::assign `to address `0x0`. `_Count` is `0` (empty string assign).

**This happens during native plugin registration**, not during Dart init.

Call site in `firebase_core` Windows (`firebase_core_plugin.cpp`):

```
void FirebaseCorePlugin::RegisterWithRegistrar(
flutter::PluginRegistrarWindows* registrar) {
auto plugin = std::make_unique();
FirebaseCoreHostApi::SetUp(registrar->messenger(), plugin.get());
FirebaseAppHostApi::SetUp(registrar->messenger(), plugin.get());
registrar->AddPlugin(std::move(plugin));
// Register for platform logging
App::RegisterLibrary(kLibraryName.c_str(), getPluginVersion().c_str(),
nullptr);
}
```
That `RegisterLibrary` call is reached from `FirebaseCorePluginCApiRegisterWithRegistrar` in `RegisterPlugins()`, while creating the Flutter Windows engine — before any Dart `Firebase.initializeApp()`.

**Isolation**

- **Release** (and typically **Profile**): app starts.
- **Debug**: crash as above.
- Commenting out `FirebaseCorePluginCApiRegisterWithRegistrar(...)` in `generated_plugin_registrant.cc` (must rebuild without letting Flutter regenerate that file): Debug **starts**.
- Restoring the call: crash returns.
- The crash is therefore this registration path (`RegisterLibrary` / platform logging), not the placement of `Firebase.initializeApp()` in Dart.

**Environment:**

- Windows 11
- Visual Studio 2026 Community (generator `Visual Studio 18 2026`)
- MSVC platform toolset v143 (VS 2026 default v145; v143 forced in CMake)
- Flutter 3.44.9 stable (Dart 3.12.2)
- `firebase_core` 4.14.0 (Firebase C++ SDK 13.11.0)
- Also in the app: `firebase_analytics` 12.5.0, `firebase_crashlytics` 5.3.0, `firebase_messaging` 16.6.0
- Windows actually uses Analytics only; Crashlytics/Messaging are not initialized on that platform. Those packages do not need to be in a minimal repro.

**Expected**

Debug `flutter run -d windows` starts the app. `App::RegisterLibrary` during plugin registration must not access-violate, especially before `Firebase.initializeApp()`.

**Actual**

Process dies in `RegisterLibrary` (`c0000005` write to `NULL`). Flutter loses the debug log reader. No Dart exception.

### Reproducing the issue

**Minimal**:

1. `flutter create firebase_windows_debug_crash`
2. `cd firebase_windows_debug_crash`
3. `flutter pub add firebase_core:4.14.0`
4. In `lib/main.dart`, after `WidgetsFlutterBinding.ensureInitialized()`:

```
await Firebase.initializeApp(
options: const FirebaseOptions(
apiKey: 'dummy',
appId: '1:1:web:1',
messagingSenderId: '1',
projectId: 'dummy',
),
);
```
(Even without this Dart call, the crash may still happen, because registration is native.)

5.`flutter run -d windows (Debug)`
If it still crashes, skip step 4 and run Debug with only the firebase_core dependency.

Observed in a real app:

1. `flutter run -d windows` (Debug) with `firebase_core: 4.14.0`.
2. Windows build succeeds (`Built ...\runner\Debug\.exe`).
3. Process starts, then exits immediately (optional warning about unmerged UI/platform threads is unrelated).
4. Attach VS 2026 to the Debug exe, break on Win32 access violation: stack below.
5. Workaround: do not call `App::RegisterLibrary` in `FirebaseCorePlugin::RegisterWithRegistrar` (or skip `FirebaseCorePluginCApiRegisterWithRegistrar`). Debug then launches.

### Firebase Core version

4.14.0

### Flutter Version

3.44.9

### Relevant Log Output

```shell
-- Flutter (Debug)
√ Built build\windows\x64\runner\Debug\checker_multiplatform.exe
Error waiting for a debug connection: The log reader stopped unexpectedly, or never started.
Error launching application on Windows.

--Visual Studio 2026 call stack:
[Exception at 0x... in .exe: 0xC0000005: access violation writing location 0x0000000000000000.]
> .exe!std::_Narrow_char_traits::assign(char & _Left, const char & _Right='\0')
.exe!std::string::assign(const char * const _Ptr=..., const unsigned __int64 _Count=0)
.exe!firebase::app_common::LibraryRegistry::RegisterLibrary(char const *, char const *)
... (unknown frames; Firebase C++ libs have no PDBs)
```

### Flutter dependencies

Expand Flutter dependencies snippet

```yaml

- firebase_analytics_platform_interface 6.0.7 [_flutterfire_internals firebase_core flutter meta plugin_platform_interface]
- firebase_analytics_web 0.6.1+13 [_flutterfire_internals firebase_analytics_platform_interface firebase_core firebase_core_web flutter flutter_web_plugins]
- firebase_core_platform_interface 8.1.1 [collection flutter meta plugin_platform_interface]
- firebase_core_web 3.11.0 [firebase_core_platform_interface flutter flutter_web_plugins meta web]
- firebase_crashlytics_platform_interface 3.9.0 [_flutterfire_internals collection firebase_core firebase_core_platform_interface flutter meta plugin_platform_interface]
- firebase_messaging_platform_interface 4.10.0 [_flutterfire_internals firebase_core flutter meta plugin_platform_interface]
- firebase_messaging_web 4.2.5 [_flutterfire_internals firebase_core firebase_core_web firebase_messaging_platform_interface flutter flutter_web_plugins meta web]
```

### Additional context and comments

Notes for maintainers:

- Debug links `...\firebase_cpp_sdk_windows\libs\windows\VS2019\MD\x64\Debug\firebase_app.lib` with `/MDd` (`MultiThreadedDebugDLL`). Release links the Release `.lib` with `/MD`. This does not look like mixing Release Firebase libs into a Debug app.
- Flutter Windows `APPLY_STANDARD_SETTINGS` defines `_HAS_EXCEPTIONS=0` (and firebase_core applies those settings to the plugin). Combined with `/EHsc`, that can change `std::string` layout vs prebuilt Firebase C++ libs.
- `RegisterLibrary` runs at plugin registration, before any `firebase::App` exists.

Start with the minimal reproduction and run `flutter run -d windows` in Debug, then inspect `firebase_core_plugin.cpp` at `FirebaseCorePlugin::RegisterWithRegistrar` and the generated call in `generated_plugin_registrant.cc`. Compare the Debug and Release behavior and use the provided Visual Studio access-violation stack to trace the registration path. Done means the Debug Windows app starts without the native crash during plugin registration.

Written by the indexing model from the issue text.