fix(bgm): hot-reload markdown definition edits

Normalize the games root to POSIX separators so the HMR path guard
matches on Windows, and watch the real on-disk markdown files (which
defMap.files omits in favor of their virtual code blocks) so edits
trigger a re-collect instead of a manual restart.

packages/bgm/src/vite.ts

@@ -16,8 +16,9 @@
  * hot-reloads the app via `addWatchFile`.
  */
 import * as path from 'node:path';
-import type { ModuleNode, Plugin } from 'vite';
+import { normalizePath, type ModuleNode, type Plugin } from 'vite';
 import { collectPackages, loadDefs } from './collect.js';
+import { readDefFiles } from './parse.js';
 import type { Package, SerializedPackage } from './types.js';
 
 const VIRTUAL_PREFIX = '\0bgm:';
@@ -32,7 +33,10 @@ export interface BgmOptions {
 }
 
 export function bgm(options: BgmOptions): Plugin {
-  const root = options.root;
+  // Vite normalizes `ctx.file` to POSIX separators before HMR hooks run, but
+  // `fileURLToPath` retains backslashes on Windows. Normalize `root` to the
+  // same form so `ctx.file.startsWith(root)` matches regardless of platform.
+  const root = normalizePath(options.root);
 
   const collect = (): Package[] => {
     const defMap = loadDefs('', root);
@@ -42,11 +46,18 @@ export function bgm(options: BgmOptions): Plugin {
   return {
     name: 'bgm',
     buildStart() {
-      // Watch every source file so edits trigger a reload/re-collect.
+      // Watch every real definition source under the games root so edits
+      // trigger a re-collect. `defMap.files` only holds the virtual code-block
+      // files plus real non-markdown files; the markdown files themselves are
+      // consumed for their code blocks and never appear there, so watch the
+      // real files on disk too (markdown and anything else the loader reads).
       const defMap = loadDefs('', root);
       for (const name of defMap.files.keys()) {
         this.addWatchFile(path.join(root, name));
       }
+      for (const file of readDefFiles(root, '')) {
+        this.addWatchFile(file.source);
+      }
     },
     resolveId(id) {
       if (id === PACKAGES) return VIRTUAL_PREFIX + PACKAGES;