Geometry Scalar should expect a WKT or a Geometry Object.

### Component
c/v3-engine

### Is your proposal related to a problem?
At the moment it's necessary to stringify the geometry object.

```gql
query find($Geometry:Geometry!){
postcode(where:{geometry:{st_contains:$Geometry}}){
number
}
}
```
```json
{
"Geometry": "{\"type\":\"Point\",\"coordinates\":[391968,5818620],\"crs\":{\"type\":\"name\",\"properties\":{\"name\":\"EPSG:25833\"}}}"
}
```

### Describe the solution you'd like
Geometry should be a Object instead of a Scalar. This would not only align with the way geometry inputs work but also enable the graphql engine and ui tools like houdini to check the validity of the input in advance. i.e. disallow geometries with an invalid type property.

```gql
query find($Geometry:Geometry!){
postcode(where:{geometry:{st_contains:$Geometry}}){
number
}
}
```
```json
{
"Geometry": {
"type": "Point",
"coordinates": [
391968,
5818620
],
"crs": {
"type": "name",
"properties": {
"name": "EPSG:25833"
}
}
}
}
```

### Describe alternatives you've considered

Start in the c/v3-engine Geometry scalar and its GraphQL input definition, then trace how the Geometry variable is validated. Confirm the expected object shape and invalid type handling before checking the existing geometry input behavior. Done means Geometry variables accept objects directly and reject invalid type values without requiring stringification.

Written by the indexing model from the issue text.