Stop using .npmignore (#30609)

Use the package.json "files" property instead of a .npmignore file.

GitOrigin-RevId: 10ab0b8280067a8553970d0b27d217ff61d04ae3

Author: thomasballinger

.npmignore

@@ -195,9 +195,32 @@
     "test": "vitest --silent",
     "test-not-silent": "vitest",
     "new-test": "vitest",
-    "test-esm": "node ./scripts/test-esm.mjs && ./scripts/checkdeps.mjs && ./scripts/checkimports.mjs",
-    "pack-internal": "echo TODO maybe set an environment variable"
+    "test-esm": "node ./scripts/test-esm.mjs && ./scripts/checkdeps.mjs && ./scripts/checkimports.mjs"
   },
+  "files": [
+    "bin",
+    "browser",
+    "config",
+    "dist",
+    "nextjs",
+    "react",
+    "react-auth0",
+    "react-clerk",
+    "server",
+    "src",
+    "values",
+    "CHANGELOG.md",
+    "LICENSE",
+    "README.md",
+    "browser-bundle.js",
+    "package.json",
+    "tsconfig.json",
+    "!*.test.*",
+    "!test",
+    "!test_fixtures",
+    "!client_node_test_helpers.*",
+    "!src/bundler/.eslintrc.cjs"
+  ],
   "keywords": [
     "convex",
     "database",