### Summary
This PR transitions the spawner system from a simple radius-based model to a flexible 3D boundary system.
### Core Changes
* **Replaced `HomeRange` with `SpawnBounds`**: Spawners now use a `Rectangle3D` to define spawn areas instead of a circular integer range.
* **Backward Compatibility**:
* The `HomeRange` property remains as a helper that generates square `SpawnBounds` centered on the spawner.
* Included a migration path (v10 to v11) that automatically converts old range data into new bounds during deserialization.
* **Dynamic Bounds Shifting**: If a spawner is moved, its `SpawnBounds` will automatically shift with it, provided the bounds are currently configured as a centered square.
* **New Spawn Logic**: Added `SpawnLocationIsHome` toggle. If enabled, spawned mobiles treat their exact spawn coordinates as their "Home" rather than the spawner's location.
### Implementation Details
* **Interface Updates**: Updated `ISpawner` to include `WalkingRange`, `SpawnBounds`, and `IsInSpawnBounds()`.
* **UI Enhancements**: The Spawner Controller Gump now displays "Custom" for complex bounds and allows copying of the new boundary properties between spawners.
* **Refactored Constructors**: Streamlined `BaseSpawner`, `ProximitySpawner`, and `RegionSpawner` constructors to support the new data types.
> [!IMPORTANT]
> This code change includes important fixes for all spawners after they were converted to codegen!
> [!NOTE]
> **Developer Note**
> Usage/Description/Aliases attributes were moved to the core so they can be used by the command registration system.
### Summary
- **Fixes spawners not registering their spawns on world load**
- Changes `[GenerateSpawners` to `[ImportSpawners`
- Removes `ConvertPremiumSpawners`
- Adds Premium spawner import support to `[ImportSpawners`
- Adds RunUO XML import support: https://github.com/ruaduck/xmlspawner/blob/ServUOMaster/XmlSpawner/XmlSpawner%20Core/SpawnerExporter.cs
- Fixed an issue where not manually registering an alias meant it wasn't available as a command
