Ask for heights through one service per scene

About 20 sites called scene.sampleHeight, globe.getHeight,
scene.clampToHeight or the MostDetailed variants directly, each with its own
idea of a miss (undefined, NaN, a throw). They now ask heightsFor(scene) in
src/queries/heights.js:

- now(point, { against, exclude }) answers from what is loaded, or null;
  against is 'surface' (what is drawn) or 'terrain' (loaded terrain only).
- clampNow(position) moves a position onto the drawn surface, or null.
- batch() and clampBatch() wait for the most detailed tiles: null per
  missed point, a rejection when the whole query fails.
- supported() reports { surface, clamp } without allocating.

Cesium still answers now() synchronously, so nothing changes on screen and
nothing is slower: in the live app 1,000 calls cost the same through the
service as direct (terrain 0.5-0.7 ms, surface 2-6 ms a call, run-to-run
noise larger than the difference). Every site already treated a miss as
"hold the last value or fall back"; a renderer that can only answer from a
cache or asynchronously can now plug in at one place.

- A Bhote Koshi evidence point whose terrain sample misses stays at its
  fallback elevation instead of reading the miss as sea level.
- The mesh floor sampler skips a scene without depth-texture support
  instead of spending its budget on probes that throw.
- The world annotation probe's trace reads hit/missed.
- A source scan forbids direct height calls outside the service.

The service is exported as ./queries/heights and documented in
docs/APPLICATION.md.

scripts/format-scope.json

@@ -47,6 +47,8 @@
   "src/input/testDoubles.mjs",
   "src/input/sensorPick.js",
   "src/input/dispatcher.js",
+  "src/queries/heights.js",
+  "src/queries/heights.test.mjs",
   "docs/CODE-BOUNDARIES.md",
   "src/main.js",
   "docs/APPLICATION.md",

scripts/package-boundaries.json

@@ -15,7 +15,8 @@
       "src/input/dispatcher.js",
       "src/input/sensorPick.js",
       "src/data/infrastructureOverlayEntry.js",
-      "src/sources/infrastructureData.js"
+      "src/sources/infrastructureData.js",
+      "src/queries/heights.js"
     ],
     "external": ["cesium"]
   },
@@ -1859,7 +1860,8 @@
       "src/i18n/locales/ru.json",
       "src/i18n/locales/uk.json",
       "src/i18n/locales/zh-CN.json",
-      "src/i18n/locales/zh-Hant.json"
+      "src/i18n/locales/zh-Hant.json",
+      "src/queries/heights.js"
     ],
     "external": ["cesium", "pbf", "@mapbox/vector-tile"]
   },
@@ -1900,7 +1902,8 @@
       "src/input/sensorPick.js",
       "src/data/scenePick.js",
       "src/data/pickRegistry.js",
-      "src/input/dispatcher.js"
+      "src/input/dispatcher.js",
+      "src/queries/heights.js"
     ],
     "external": ["cesium"]
   },
@@ -2046,7 +2049,8 @@
       "src/data/scenePick.js",
       "src/input/sensorPick.js",
       "src/data/pickRegistry.js",
-      "src/input/dispatcher.js"
+      "src/input/dispatcher.js",
+      "src/queries/heights.js"
     ],
     "external": ["cesium", "pbf", "@mapbox/vector-tile", "mapillary-js"]
   },
@@ -2089,7 +2093,8 @@
       "src/input/sensorPick.js",
       "src/data/scenePick.js",
       "src/data/pickRegistry.js",
-      "src/input/dispatcher.js"
+      "src/input/dispatcher.js",
+      "src/queries/heights.js"
     ],
     "external": ["cesium", "@mapbox/vector-tile", "pbf"]
   },
@@ -3327,7 +3332,8 @@
       "src/data/local_data/wof_neighborhoods/files.js",
       "src/data/entityRecords.js",
       "src/input/sensorPick.js",
-      "src/input/dispatcher.js"
+      "src/input/dispatcher.js",
+      "src/queries/heights.js"
     ],
     "external": [
       "hls.js",
@@ -3952,7 +3958,8 @@
       "src/data/local_data/wof_neighborhoods/files.js",
       "src/data/entityRecords.js",
       "src/input/sensorPick.js",
-      "src/input/dispatcher.js"
+      "src/input/dispatcher.js",
+      "src/queries/heights.js"
     ],
     "external": [
       "hls.js",
@@ -4039,7 +4046,8 @@
       "src/data/placeBoundaries.js",
       "src/data/placeNames.js",
       "src/data/local_data/us_census_places/files.js",
-      "src/data/local_data/wof_neighborhoods/files.js"
+      "src/data/local_data/wof_neighborhoods/files.js",
+      "src/queries/heights.js"
     ],
     "external": [
       "cesium",
@@ -4647,7 +4655,8 @@
       "src/i18n/locales/zh-CN.json",
       "src/i18n/locales/zh-Hant.json",
       "src/input/sensorPick.js",
-      "src/input/dispatcher.js"
+      "src/input/dispatcher.js",
+      "src/queries/heights.js"
     ],
     "external": ["cesium", "egm96-universal", "pbf"]
   },
@@ -4703,7 +4712,8 @@
       "src/input/sensorPick.js",
       "src/data/scenePick.js",
       "src/data/pickRegistry.js",
-      "src/input/dispatcher.js"
+      "src/input/dispatcher.js",
+      "src/queries/heights.js"
     ],
     "external": ["cesium", "pbf"]
   },
@@ -4869,7 +4879,8 @@
       "src/data/scenePick.js",
       "src/input/sensorPick.js",
       "src/data/pickRegistry.js",
-      "src/input/dispatcher.js"
+      "src/input/dispatcher.js",
+      "src/queries/heights.js"
     ],
     "external": ["cesium"]
   },
@@ -5101,5 +5112,10 @@
       "src/i18n/marker.js"
     ],
     "external": ["cesium"]
+  },
+  "heights": {
+    "exports": ["./queries/heights"],
+    "modules": ["src/queries/heights.js"],
+    "external": ["cesium"]
   }
 }