refactor(bgm): use virtual: module specifiers

Rename the plugin's virtual modules to virtual:bgm/packages and
virtual:bgm/package/<id> so they read as plugin-provided modules rather
than real packages. Update the unit and build integration tests.

packages/bgm/src/vite.ts

@@ -1,10 +1,19 @@
 /**
- * Vite plugin: resolve `bgm/<package>` imports to the package's JSON.
+ * Vite plugin: resolve `virtual:bgm/packages` and `virtual:bgm/package/<id>`
+ * imports to JSON.
  *
  * The loader reads a games root (markdown code blocks + real
- * yaml/json/toml/csv files), collects packages, and this plugin serves each
- * package as a module whose default export is the assembled JSON. Editing a
- * game definition hot-reloads the app via `addWatchFile`.
+ * yaml/json/toml/csv files), collects packages, and this plugin serves them
+ * as modules:
+ *
+ * - `virtual:bgm/packages` — the default export is an array of every
+ *   discovered package.
+ * - `virtual:bgm/package/<id>` — the default export is that single package's
+ *   assembled JSON.
+ *
+ * The `virtual:` prefix marks these as plugin-provided modules, so they can't
+ * be mistaken for real installed packages. Editing a game definition
+ * hot-reloads the app via `addWatchFile`.
  */
 import * as path from 'node:path';
 import type { Plugin } from 'vite';
@@ -12,6 +21,10 @@ import { collectPackages, loadDefs } from './collect.js';
 import type { Package } from './types.js';
 
 const VIRTUAL_PREFIX = '\0bgm:';
+/** Public specifier for the module that lists every package. */
+const PACKAGES = 'virtual:bgm/packages';
+/** Public specifier prefix for a single package module. */
+const PACKAGE = 'virtual:bgm/package/';
 
 export interface BgmOptions {
   /** Absolute path to the games root (e.g. `<repo>/games`). */
@@ -36,11 +49,17 @@ export function bgm(options: BgmOptions): Plugin {
       }
     },
     resolveId(id) {
-      if (id.startsWith('bgm/')) return VIRTUAL_PREFIX + id;
+      if (id === PACKAGES) return VIRTUAL_PREFIX + PACKAGES;
+      if (id.startsWith(PACKAGE)) return VIRTUAL_PREFIX + id;
     },
     load(id) {
       if (!id.startsWith(VIRTUAL_PREFIX)) return;
-      const name = id.slice(VIRTUAL_PREFIX.length + 'bgm/'.length);
+      const virtual = id.slice(VIRTUAL_PREFIX.length);
+      if (virtual === PACKAGES) {
+        const packages = collect().map(toJson);
+        return `export default ${JSON.stringify(packages)}`;
+      }
+      const name = virtual.slice(PACKAGE.length);
       const pkg = collect().find((p) => p.meta.id === name);
       if (!pkg) {
         throw new Error(`bgm package "${name}" not found`);