fix(package): pack dist/src and src only, not the compiled test suite

changelog.d/package-files.fixed.md

@@ -0,0 +1,6 @@
+- The npm package no longer ships the compiled test suite or the
+  compiler's build record: `files` packs `dist/src` and `src`, so
+  `dist/test`, about half the published files, and
+  `dist/tsconfig.tsbuildinfo` stay out, and the package's contents no
+  longer depend on whether the tests ran before packing. The redundant
+  `discord.js` entry in `devDependencies` is gone (it is a dependency).

package.json

@@ -17,7 +17,7 @@
     }
   },
   "files": [
-    "dist",
+    "dist/src",
     "src"
   ],
   "bin": {
@@ -58,7 +58,6 @@
     "@babel/parser": "^7.29.9",
     "@types/node": "^22.0.0",
     "@types/ws": "^8.5.13",
-    "discord.js": "^14.25.1",
     "tsx": "^4.21.0",
     "typescript": "^7.0.2"
   },