Fix feature ID double-to-string format mismatch in JNI marshaling (#10615)

### Summary

Fixes https://mapbox.atlassian.net/browse/MAPSAND-2531

- Fix incorrect string formatting of `double` feature IDs in JNI
marshaling
- Whole-number `double` IDs (e.g., `12345.0`) are now serialized as
`"12345"` instead of `"12345.000000"`

### Problem

Feature IDs in mapbox-feature are a `std::variant<uint64_t, int64_t,
double, null_value_t>`. The previous code used a single generic `auto&`
lambda to handle all numeric types, which called `std::to_string()`
directly on the value. For `double` IDs that represent whole numbers
(e.g., `12345.0`), this produced `"12345.000000"` on the JNI/Java side —
causing ID mismatches when compared against integer-typed IDs stored
elsewhere in the system.

### Solution

Split the single generic numeric handler in `feature.hpp` into three
type-specific lambdas:

- **`uint64_t`** and **`int64_t`**: call `std::to_string()` directly →
`"12345"`
- **`double`**: use `std::modf` to check if the value is a whole number,
finite, and within `int64_t` range; if so, cast to `int64_t` before
formatting → `"12345"` instead of `"12345.000000"`; otherwise format
as-is to preserve fractional precision

Added `StandardBuildingsFeatureStateTest` instrumentation test verifying
that feature IDs from `queryRenderedFeatures` are compatible with
`setFeatureState`/`getFeatureState`.

### Validation

Validated on device that clicking buildings with
`ClickInteraction.standardBuildings` + `setFeatureState` works correctly
with the fix applied.

cc @mapbox/maps-android @mapbox/core-sdk @mapbox/sdk-platform

GitOrigin-RevId: 4289724877a9f11917ca1d95c06e0c84076b7173

Author: pengdev

CHANGELOG.md

@@ -7,6 +7,7 @@ Mapbox welcomes participation and contributions from everyone.
 # main
 ## Bug fixes 🐞
 * Fix native memory leak in `AnnotationManager` where bitmap style images were not removed onDestroy.
+* Fix feature ID format mismatch in JNI marshaling where whole-number `double` feature IDs (e.g. `12345.0`) were incorrectly serialized as `"12345.000000"` instead of `"12345"`, causing `setFeatureState` to fail when using IDs obtained from `queryRenderedFeatures`.
 
 # 11.20.1 March 17, 2026
 ## Bug fixes 🐞

app/src/androidTest/java/com/mapbox/maps/testapp/featurestate/StandardBuildingsFeatureStateTest.kt

@@ -0,0 +1,78 @@
+package com.mapbox.maps.testapp.featurestate
+
+import androidx.test.ext.junit.runners.AndroidJUnit4
+import com.mapbox.geojson.Point
+import com.mapbox.maps.MapboxExperimental
+import com.mapbox.maps.Style
+import com.mapbox.maps.dsl.cameraOptions
+import com.mapbox.maps.interactions.standard.generated.StandardBuildings
+import com.mapbox.maps.interactions.standard.generated.StandardBuildingsState
+import com.mapbox.maps.testapp.BaseMapTest
+import com.mapbox.maps.testapp.runOnUiThread
+import com.mapbox.maps.testapp.withLatch
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertNotNull
+import org.junit.Test
+import org.junit.runner.RunWith
+
+/**
+ * Instrumented test verifying that feature IDs returned by [com.mapbox.maps.MapboxMap.queryRenderedFeatures]
+ * for StandardBuildings are compatible with [com.mapbox.maps.MapboxMap.setFeatureState] and
+ * [com.mapbox.maps.MapboxMap.getFeatureState].
+ *
+ * Regression test for: double feature IDs being formatted as "12345.000000" instead of "12345"
+ * due to a format mismatch in JNI marshaling (feature.hpp).
+ */
+@OptIn(MapboxExperimental::class)
+@RunWith(AndroidJUnit4::class)
+class StandardBuildingsFeatureStateTest : BaseMapTest() {
+
+  override fun loadMap() {
+    withLatch(timeoutMillis = 30000) { latch ->
+      rule.runOnUiThread {
+        mapboxMap = mapView.mapboxMap
+        mapboxMap.setCamera(
+          cameraOptions {
+            center(Point.fromLngLat(24.94180921290157, 60.171227338006844))
+            zoom(16.0)
+          }
+        )
+        mapboxMap.loadStyle(Style.STANDARD) { style ->
+          this@StandardBuildingsFeatureStateTest.style = style
+          // Wait for the map to finish rendering tiles before querying features
+          mapboxMap.subscribeMapIdle {
+            latch.countDown()
+          }
+        }
+      }
+    }
+  }
+
+  /**
+   * Verifies that a building queried via [com.mapbox.maps.MapboxMap.queryRenderedFeatures] can
+   * have its state set and retrieved using the typed featureset API.
+   *
+   * If the feature ID format is wrong (e.g. "12345.000000"), setFeatureState will target a
+   * different feature and getFeatureState will return null for select, causing the assertion
+   * to fail.
+   */
+  @Test
+  fun testQueryRenderedBuildingIdCompatibleWithSetFeatureState() {
+    withLatch(timeoutMillis = 10000) { latch ->
+      rule.runOnUiThread {
+        mapboxMap.queryRenderedFeatures(StandardBuildings()) { buildings ->
+          val building = buildings.firstOrNull { it.id != null }
+          assertNotNull("Expected at least one rendered building with an ID", building)
+          building!!
+
+          mapboxMap.setFeatureState(building, StandardBuildingsState { select(true) }) {
+            mapboxMap.getFeatureState(building) { state ->
+              assertEquals(true, state.select)
+              latch.countDown()
+            }
+          }
+        }
+      }
+    }
+  }
+}