build: the initial-chunk guard covers Navara's whole dependency closure

Review of Task 0:
- build/navaraDependencies.js reads the dependency closure of
  @navaramap/three and @navaramap/three-default-plugin from node_modules
  (dependencies and peers) and drops what the app's other bundled
  dependencies reach too (Cesium is served as a script, so draco3d, which
  only Cesium shares, stays engine-only), plus three and postprocessing:
  88 packages today (the @navaramap/* packages, @takram/*, @react-three/
  fiber, @sparkjsdev/spark, astronomy-engine, d3*, draco3d, n8ao,
  three-stdlib, …). The browser build's initialChunkGuard fails on a
  module from any of them in an initial chunk. Tested on a fixture tree.
- check-main-chunk's budget measures the entry the page loads (the same
  chunk the composition check reads), falling back to phase 4's largest
  index-*.js only for a dist without a page.

Build clean: no Navara-only module in the initial chunks; main chunk
2,869,565 bytes (gzip 889,041).

scripts/check-main-chunk.mjs

@@ -42,8 +42,28 @@ export function checkMainChunk(
   };
 }
 
-/** gzip-9 size of the largest dist/assets/index-*.js, with its name. */
-export function measureMainChunk(distDir) {
+/**
+ * gzip-9 size of the main chunk, with its name: the entry the built page
+ * loads (`entry`, or found from dist/index.html or the Vite manifest), else
+ * (phase 4's rule, for a dist without a page) the largest
+ * dist/assets/index-*.js.
+ */
+export function measureMainChunk(distDir, { entry = null } = {}) {
+  let file = entry;
+  if (!file) {
+    try {
+      file = findEntry(distDir).entry;
+    } catch {
+      file = null;
+    }
+  }
+  if (file) {
+    const bytes = fs.readFileSync(path.join(distDir, file));
+    return {
+      name: path.basename(file),
+      gzipBytes: gzipSync(bytes, { level: 9 }).length,
+    };
+  }
   const assets = path.join(distDir, 'assets');
   const candidates = fs
     .readdirSync(assets)
@@ -113,7 +133,7 @@ function main() {
   const baselinePath = path.join(ROOT, 'scripts/main-chunk-baseline.json');
   let budget = null;
   if (fs.existsSync(baselinePath)) {
-    const measured = measureMainChunk(dist);
+    const measured = measureMainChunk(dist, { entry: composition.entry });
     budget = {
       ...measured,
       ...checkMainChunk(

scripts/format-scope.json

@@ -1082,5 +1082,8 @@
   "src/globe/navara/picking.test.mjs",
   "src/data/selectionDispatcher.test.mjs",
   "src/globe/navara/cascadedLightCopy.test.mjs",
-  "src/tooling/w1Feeds.test.mjs"
+  "src/tooling/w1Feeds.test.mjs",
+  "src/tooling/navaraDependencies.test.mjs",
+  "build/navaraDependencies.js",
+  "build/initialChunkGuard.js"
 ]