[FEAT]: Make meshing workflow types directly constructible based on server context.

### ❓ Problem statement

Make the (Meshing)Workflow types directly constructible based on a meshing session context.
That will help clarify the meshing documentation and make it fully self-contained.

### 💡 Proposed solution
```
meshing = <meshing session>

WatertightMeshing(session=meshing)
```

### 🔀 Alternatives considered

_No response_

### 📌 Additional context

_No response_