build: reach Navara only through import() and ship its worker wasm

The import-direction check now tells dynamic imports apart
(analyzeModule(source, { dynamic: true })) and rejects any static import
or re-export of src/globe/navara/** from outside that directory, so the
Navara engine can only be a lazily loaded chunk of the app.

Navara's prebuilt workers load their wasm by file name next to
themselves, which the bundler cannot see; a build-only Rollup plugin
copies the missing ones (draco decoder, font worker) into assets/ when
the bundle includes Navara, and adds nothing to a build without it.

src/tooling/importDirections.test.mjs

@@ -241,6 +241,44 @@ for (const [name, files, pattern] of [
   });
 }
 
+test('module analysis can tell dynamic imports from static ones', () => {
+  assert.deepEqual(
+    analyzeModule(
+      "import a from 'one'; export * from 'two'; import('three'); const x = () => import('four');",
+      { dynamic: true },
+    ),
+    {
+      imports: ['one', 'two', 'three', 'four'],
+      browser: [],
+      dynamicImports: ['three', 'four'],
+    },
+  );
+});
+
+test('the app reaches the Navara engine only through a dynamic import', (t) => {
+  const { root, write } = fixture(t);
+  write('src/globe/navara/index.js', "import './engine.js';");
+  write('src/globe/navara/engine.js', '');
+  write(
+    'src/app/scene.js',
+    "export const load = () => import('../globe/navara/index.js');",
+  );
+  assert.doesNotThrow(() => checkImportDirections(root));
+  write('src/app/scene.js', "import '../globe/navara/index.js';");
+  assert.throws(
+    () => checkImportDirections(root),
+    /src\/app\/scene\.js: The Navara engine loads only through a dynamic import\(\): src\/globe\/navara\/index\.js/,
+  );
+  write(
+    'src/app/scene.js',
+    "export { createNavaraGlobe } from '../globe/navara/index.js';",
+  );
+  assert.throws(
+    () => checkImportDirections(root),
+    /only through a dynamic import/,
+  );
+});
+
 test('geo modules may import each other, and its tests may import cesium', (t) => {
   const { root, write } = fixture(t);
   write('src/geo/math.js', 'export const half = (value) => value / 2;');

src/tooling/navaraAssets.test.mjs

@@ -0,0 +1,56 @@
+import test from 'node:test';
+import assert from 'node:assert/strict';
+import { mkdtempSync, rmSync, writeFileSync } from 'node:fs';
+import os from 'node:os';
+import path from 'node:path';
+import { navaraWorkerAssets } from '../../build/navaraAssets.js';
+import { createBrowserViteConfig } from '../../build/vite.js';
+
+test('the build copies the wasm files Navara workers load by name next to them', (t) => {
+  const dir = mkdtempSync(path.join(os.tmpdir(), 'gev-navara-assets-'));
+  t.after(() => rmSync(dir, { recursive: true, force: true }));
+  writeFileSync(path.join(dir, 'draco_decoder-AAAA.wasm'), 'draco');
+  writeFileSync(path.join(dir, 'navara_wasm_worker_bg-BBBB.wasm'), 'worker');
+  writeFileSync(path.join(dir, 'fontWorker-CCCC.js'), 'not wasm');
+  const plugin = navaraWorkerAssets({ assetsDir: dir });
+  const emitted = [];
+  const bundle = {
+    // Rollup already emitted this one under the same name.
+    'assets/navara_wasm_worker_bg-BBBB.wasm': { type: 'asset' },
+    // A Navara worker chunk shows the build includes Navara.
+    'assets/index-DDDD.js': { type: 'chunk', code: 'navara_wasm_worker_bg' },
+  };
+  plugin.generateBundle.call(
+    { emitFile: (file) => emitted.push(file) },
+    {},
+    bundle,
+  );
+  assert.deepEqual(
+    emitted.map(({ fileName, type }) => [fileName, type]),
+    [['assets/draco_decoder-AAAA.wasm', 'asset']],
+  );
+  assert.equal(String(emitted[0].source), 'draco');
+});
+
+test('a build without Navara gets no Navara wasm', (t) => {
+  const dir = mkdtempSync(path.join(os.tmpdir(), 'gev-navara-assets-'));
+  t.after(() => rmSync(dir, { recursive: true, force: true }));
+  writeFileSync(path.join(dir, 'draco_decoder-AAAA.wasm'), 'draco');
+  const plugin = navaraWorkerAssets({ assetsDir: dir });
+  const emitted = [];
+  plugin.generateBundle.call(
+    { emitFile: (file) => emitted.push(file) },
+    {},
+    { 'assets/index-EEEE.js': { type: 'chunk', code: 'cesium only' } },
+  );
+  assert.deepEqual(emitted, []);
+});
+
+test('the browser build runs the Navara asset copy as a Rollup plugin', () => {
+  const { build } = createBrowserViteConfig({});
+  assert.deepEqual(
+    build.rollupOptions.plugins.map(({ name }) => name),
+    ['navara-worker-assets'],
+  );
+  assert.equal(build.chunkSizeWarningLimit, 1500);
+});