Nest extraData by section for clearer embedding content

Homebox's location fields were flattened into single-purpose keys
(locationName/locationDescription), which gave EmbeddingService no
way to group related fields when rendering vector-store content.
extraData is now Map<String, Map<String, Object>>, letting
HomeboxItemClient express "location" as its own section; buildExtraData
renders each section as a header with indented fields instead of a flat
"Extradata: key: value" line.

backend/src/main/java/com/vaessl/app/homebox/HomeboxItemClient.java

@@ -1,6 +1,6 @@
 package com.vaessl.app.homebox;
 
-import java.util.HashMap;
+import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import org.springframework.data.domain.Page;
@@ -73,12 +73,18 @@ public class HomeboxItemClient {
             String description = i.description();
 
             HomeboxParent parent = i.parent();
-            Map<String, Object> extraData = new HashMap<>();
+            Map<String, Map<String, Object>> extraData = new LinkedHashMap<>();
+            Map<String, Object> locationData = new LinkedHashMap<>();
+
             if (parent.name() != null && !parent.name().isBlank()) {
-                extraData.put("locationName", parent.name());
+                locationData.put("name", parent.name());
             }
             if (parent.description() != null && !parent.description().isBlank()) {
-                extraData.put("locationDescription", parent.description());
+                locationData.put("description", parent.description());
+            }
+
+            if (locationData != null && !locationData.isEmpty()) {
+                extraData.put("location", locationData);
             }
 
             return new ServiceItem(id, title, description, extraData);

backend/src/main/java/com/vaessl/app/shared/ServiceItem.java

@@ -4,7 +4,7 @@ import java.util.Map;
 import jakarta.validation.constraints.NotNull;
 
 public record ServiceItem(String id, @NotNull String title, String description,
-        Map<String, Object> extraData) {
+        Map<String, Map<String, Object>> extraData) {
 
     public String getExtra(String key) {
         if (extraData == null) {

backend/src/main/java/com/vaessl/app/vector/EmbeddingService.java

@@ -4,6 +4,7 @@ import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Map.Entry;
 import org.springframework.ai.document.Document;
 import org.springframework.ai.vectorstore.VectorStore;
 import org.springframework.ai.vectorstore.filter.FilterExpressionBuilder;
@@ -54,21 +55,30 @@ public class EmbeddingService {
         return new Document(connectionId + ":" + item.id(), content, metadata);
     }
 
-    private String buildExtraData(Map<String, Object> extraData) {
+    private String buildExtraData(Map<String, Map<String, Object>> extraData) {
         if (extraData == null) {
             return "";
         }
+
+        StringBuilder formattedData = new StringBuilder();
+
+        for (Entry<String, Map<String, Object>> entry : extraData.entrySet()) {
             StringBuilder data = new StringBuilder();
-        for (Map.Entry<String, Object> entry : extraData.entrySet()) {
             if (entry.getValue() == null || entry.getValue().toString().isEmpty()) {
                 continue;
             }
-            if (!data.isEmpty()) {
+
-                data.append(" \n");
+            if (entry.getValue().entrySet() != null
+                    && !entry.getValue().entrySet().toString().isEmpty()) {
+                for (Entry<String, Object> nestedEntry : entry.getValue().entrySet()) {
+                    data.append("   ").append(nestedEntry.getKey()).append(": ")
+                            .append(nestedEntry.getValue()).append("\n");
                 }
-            data.append(entry.getKey()).append(": ").append(entry.getValue());
             }
-        return data.toString();
+
+            formattedData.append(entry.getKey()).append(": ").append("\n").append(data.toString());
+        }
+        return formattedData.toString();
     }
 
     private Map<String, Object> buildMetadata(ServiceItem item, ServiceType serviceType,
@@ -81,12 +91,13 @@ public class EmbeddingService {
     }
 
     private String buildContent(ServiceItem item, String extraData) {
-        StringBuilder content = new StringBuilder("Title: ").append(item.title());
+        StringBuilder content = new StringBuilder("title: ").append(item.title());
         if (item.description() != null && !item.description().isEmpty()) {
-            content.append("\nDescription: ").append(item.description());
+            content.append("\ndescription: ").append(item.description());
         }
         if (!extraData.isEmpty()) {
-            content.append("\nExtradata: ").append(extraData);
+
+            content.append("\n").append(extraData);
         }
         return content.toString();
     }

backend/src/test/java/com/vaessl/app/search/SearchControllerTest.java

@@ -72,7 +72,7 @@ class SearchControllerTest {
                 .andExpect(status().isOk())
                 .andExpect(jsonPath("$.content[0].title").value("MacBook Pro A1398"))
                 .andExpect(jsonPath("$.totalElements").value(1))
-                .andExpect(jsonPath("$.content[0].extraData.locationName")
+                .andExpect(jsonPath("$.content[0].extraData.location.name")
                         .value("Server Schrank Ikea weiß"));
     }
 

backend/src/test/java/com/vaessl/app/search/SearchResponseTest.java

@@ -18,7 +18,7 @@ class SearchResponseTest {
     @Test
     void shouldReturnNullWhenExtraDataKeyIsMissing() {
 
-        ServiceItem response = new ServiceItem(MOCK_ID, MOCK_TITLE, MOCK_DESCRIPTION, Map.of("key", "value"));
+        ServiceItem response = new ServiceItem(MOCK_ID, MOCK_TITLE, MOCK_DESCRIPTION, Map.of("key", Map.of("key", "value")));
 
         assertThat(response.getExtra("missing")).isNull();
     }
@@ -26,7 +26,8 @@ class SearchResponseTest {
     @Test
     void shouldReturnExtraDataValue() {
 
-        ServiceItem response = new ServiceItem(MOCK_ID, MOCK_TITLE, MOCK_DESCRIPTION, Map.of("key", "value"));
+        ServiceItem response = new ServiceItem(MOCK_ID, MOCK_TITLE, MOCK_DESCRIPTION, Map.of("key", 
+                Map.of("key", "value")));
 
         assertThat(response.id()).isEqualTo(MOCK_ID);
         assertThat(response.getExtra("key")).contains("value");