[Bug][python] YAML workflow loader cannot resolve task_type "K8S" (Kubernetes.yaml example fails to parse)

The shipped example `examples/yaml_define/Kubernetes.yaml` declares `task_type: K8S` but fails to load:

```
pydolphinscheduler.exceptions.PyDSTaskNoFoundException: cant not find task K8S
```

The YAML loader resolves a task type to its task class **by class name only**. In
`src/pydolphinscheduler/core/yaml_workflow.py`, `get_task_cls()` builds
`{type_.capitalize(): type_ for type_ in tasks.__all__}` and looks up
`task_type.capitalize()`. So it expects `"Kubernetes"` (the class name), but the
documented/constant task type is `K8S`:

- `"K8S".capitalize()` → `"K8s"`, which is **not** in the class-name map.
- The internal constant is `TaskType.KUBERNETES = "K8S"` (`constants.py`), i.e. the
rest of the SDK and the backend use `"K8S"`, but the YAML loader never consults
`TaskType` — only class names. The loader and the rest of the SDK disagree on the
K8S identifier.

There is a **second** bug in the same example: it uses camelCase field names
`minCpuCores` / `minMemorySpace`, but the `Kubernetes` task constructor expects
snake_case `min_cpu_cores` / `min_memory_space`. After getting past the loader you
then hit:

```
TypeError: __init__() missing 2 required positional arguments: 'min_cpu_cores' and 'min_memory_space'
```

**Why CI never caught it**

`Kubernetes.yaml` is the only one of the 22 examples **omitted** from the parametrize list in
`tests/core/test_yaml_workflow.py::test_get_create_workflow` (all others are covered).
So the broken example ships untested and CI stays green.

**To Reproduce**

```python
from pydolphinscheduler.core.yaml_workflow import create_workflow
create_workflow("examples/yaml_define/Kubernetes.yaml")
# -> PyDSTaskNoFoundException: cant not find task K8S
```

Or just the resolver:

```python
from pydolphinscheduler.core.yaml_workflow import get_task_cls
get_task_cls("K8S") # -> PyDSTaskNoFoundException: cant not find task K8S
get_task_cls("Kubernetes") # OK (only the class name works today)
```

**Which version are you using?**

Reproduced on:
- **PyPI release `apache-dolphinscheduler` 4.1.0** (latest release).
- **`main` branch HEAD** — `get_task_cls`, `Kubernetes.yaml`, and the parametrize
list are byte-for-byte the same as 4.1.0, confirming this is a current defect
rather than a released-only regression.

**Expected behavior**

`task_type: K8S` (the documented constant value) should resolve to the `Kubernetes`
task class, and the shipped `Kubernetes.yaml` example should parse and be covered by CI.

**Additional context**

I'll open a PR that (1) makes the loader fall back to `TaskType` constant values,
(2) fixes the camelCase fields in the example, and (3) adds the example +
`K8S`/`k8s`/`Kubernetes` cases to the tests.

Bắt đầu với src/pydolphinscheduler/core/yaml_workflow.py::get_task_cls(), sau đó kiểm tra constants.py, examples/yaml_define/Kubernetes.yaml và tests/core/test_yaml_workflow.py::test_get_create_workflow. Xác minh rằng các định danh K8S và các trường Kubernetes dạng snake_case được xử lý, đồng thời ví dụ này được đưa vào phạm vi bao phủ kiểm thử cho việc phân tích cú pháp thành công.

Do mô hình lập chỉ mục viết ra từ nội dung của issue.