perf(site): compile the engine from its sources and drop the directory facade chunk

packages/engine/AGENTS.md

@@ -23,6 +23,8 @@ Do not import the application, legacy runtime, or object-specific configuration.
 - Every source file, test, tool, and generated source is limited to 600 physical lines, including blanks/comments.
 - `pnpm lint:packages` enforces the limit. Split code by responsibility; keep bulk prepared data outside source code.
 - Maintain README.md and CLAUDE.md as a symlink to this guide. Test behavior and package boundaries.
+- The site's client build compiles the main entry from its sources and marks every module free of side effects
+  ([package-sources.mts](../../site/build/package-sources.mts)), so modules declare and export only.
 
 Numeric camera orientation math, heliocentric geometry and solar direction conversions live in `src/navigation/` and `src/solar-system/`, exported by the main entry. They depend on core numerics; no renderer, DOM or resource-loading implementation is imported. Flat solar matrices use the public `FlatMatrix3` name; navigation `Matrix3` remains nested.
 

site/build/package-sources.mts

@@ -3,16 +3,19 @@ import { fileURLToPath } from 'node:url';
 import type { Plugin } from 'vite';
 import rendererConfig from '../../packages/renderer/tsup.config.ts';
 import objectsConfig from '../../packages/objects/tsup.config.ts';
+import engineConfig from '../../packages/engine/tsup.config.ts';
 
 // tsup's shared chunks reach the client bundler as single modules, so one startup import pulled every
 // renderer module sharing that chunk (the universe, volume and star runtimes) into the first load, and every
-// object contract the objects package's one bundle holds into the chunk of its first importer.
+// object contract the objects package's one bundle holds into the chunk of its first importer. The engine's one bundle
+// did the same: the startup cover's single `smoothstep` put the whole engine (29.6 KB of 50.8 KB) in every page's first load.
 // The client build compiles the same entries from their TypeScript sources and splits per module.
-// Renderer and objects modules only declare and export, so an unused one is dropped rather than kept for its
+// Renderer, objects and engine modules only declare and export, so an unused one is dropped rather than kept for its
 // load-time effects; worker entries keep theirs. Server rendering and Node tools keep the built packages.
 const packages: readonly { name: string; directory: string; config: unknown }[] = [
   { name: '@cssearth/renderer', directory: 'renderer', config: rendererConfig },
-  { name: '@cssearth/objects', directory: 'objects', config: objectsConfig }];
+  { name: '@cssearth/objects', directory: 'objects', config: objectsConfig },
+  { name: '@cssearth/engine', directory: 'engine', config: engineConfig }];
 const built = packages.map(({ name, directory, config }) => {
   const root = fileURLToPath(new URL(`../../packages/${directory}/`, import.meta.url));
   return { name, sources: `${root}src/`, entries: new Map<string, string>(entryPairs(config, root).map(([output, source]) => [`${root}dist/${output}.js`, source])) };

site/scene/object-adapter.mts

@@ -1,6 +1,8 @@
 import { importPackagedObjectRuntime } from './scene-imports.mts';
 import { parseObjectDescriptor, type ObjectDescriptor } from '@cssearth/objects';
 import type { ObjectEntry } from '../directory/objects.mts';
+// The router that holds this adapter imports the directory statically, so a dynamic import here only added a facade chunk.
+import { loadObject } from '../directory/object-directory.mts';
 
 export const objectAdapter = Object.freeze({
   /** A page's own prepared descriptor mounts without the registry, so the first body loads before it. */
@@ -12,8 +14,7 @@ export const objectAdapter = Object.freeze({
       const { loadPackagedObject } = await importPackagedObjectRuntime();
       mount = await loadPackagedObject(preparedDescriptor, signal);
     } else {
-      const directory = objects ? null : await import('../directory/object-directory.mts');
-      const loaded = directory ? await directory.loadObject(objectId) : objects!.find(({ id }) => id === objectId);
+      const loaded = objects ? objects.find(({ id }) => id === objectId) : await loadObject(objectId);
       const objectRecord = loaded ?? null;
       if (!objectRecord) throw new Error(`Unknown cssEarth object: ${objectId ?? "unknown"}.`);
       mount = await objectRecord.loadScene(signal);