fix: add bare module name stubs to browser field for browserify

browserify resolves dynamic import("fs/promises") as bare module
names, not node:-prefixed. Add both variants so browserify stubs
them correctly in browser builds.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: niconiconi

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@ocash/sdk",
-  "version": "0.1.2",
+  "version": "0.1.3",
   "description": "OCash ZKP SDK for browser, hybrid and Node runtimes",
   "license": "MIT",
   "repository": {
@@ -50,7 +50,11 @@
     "better-sqlite3": false,
     "node:sqlite": false,
     "node:fs/promises": false,
-    "node:path": false
+    "node:path": false,
+    "fs": false,
+    "fs/promises": false,
+    "path": false,
+    "sqlite": false
   },
   "files": [
     "dist",