Fix OntoPortal response format

[Imene-Amirat]

When calling the api-gateway /search endpoint with targetDbSchema=ontoportal, the response does not match the native OntoPortal /search format.

Missing fields

Field	Expected	Current
matchType	"prefLabel", "synonym", "definition"	null
ontologyType	"ONTOLOGY", "THESAURUS"	null
@id	concept IRI	absent
@type	"http://www.w3.org/2002/07/owl#Class"	absent
totalCount	real value (35475)	limited to 100
pageCount	real value (710)	2 (based on limited totalCount)

Example

Raw gateway response: /search?query=water&database=ontoportal&targetDbSchema=ontoportal

{
  "pageCount": 1,
  "nextPage": null,
  "prevPage": null,
  "links": {
      "nextPage": null,
      "prevPage": null
  },
  "page": 1,
  "collection": [
      {
          "iri": "https://w3id.org/ozcar-theia/c_bee9796f",
          "backend_type": "ontoportal",
          "@type": "THEIA_THES",
          "prefLabel": "Water",
          "short_form": "c_bee9796f",
          "source": "https://data.earthportal.eu",
          "type": "http://www.w3.org/2002/07/owl#Class"
      },
   ]
}
                                         
                                                                                                                                                                                                                                             
                                                                                                                                                                                                                                  
Expected OntoPortal response:
{
  "totalCount": 35475,       
  "collection": {                                                                                                                                                                                                                    
    "@id": "https://w3id.org/ozcar-theia/c_bee9796f",
    "@type": "http://www.w3.org/2002/07/owl#Class",  
    "prefLabel": "Water",                                                                                                                                                                                                           
    "matchType": "prefLabel",                 
    "ontologyType": "ONTOLOGY",                                                                                                                                                                                                                                                                                                                                                                                                      
}                                           

• Increase pagesize to 150 on the OntoPortal /search endpoint — the current default returns just 100 results compared to what OntoPortal itself exposes.
• Replace the alphabetical sort with cosine-similarity ranking or Lucene