feat: add fuzz testing harnesses and fix build dependencies

- Add fuzz testing harnesses for `nostrEventSchemas.js`, `dmDecryptor.js`, and `magnetUtils.js`.
- Move build-critical devDependencies (`cross-env`, `esbuild`, `nostr-tools`) to dependencies to fix Netlify deployment failure.
- Harmonize fuzzing iterations to 50,000.
- Add documentation headers to fuzz scripts.
- Verified robustness of fuzz targets (no crashes found).

Co-authored-by: PR0M3TH3AN <[email protected]>

package.json

@@ -35,10 +35,7 @@
   "devDependencies": {
     "@noble/hashes": "^2.0.1",
     "@playwright/test": "^1.58.0",
-    "cross-env": "^10.1.0",
-    "esbuild": "^0.25.12",
     "fake-indexeddb": "^6.2.5",
-    "nostr-tools": "^2.19.4",
     "pixelmatch": "^5.3.0",
     "playwright": "^1.58.0",
     "pngjs": "^7.0.0",
@@ -53,7 +50,10 @@
     "@noble/hashes": "^2.0.1",
     "@tailwindcss/typography": "^0.5.19",
     "autoprefixer": "^10.4.24",
+    "cross-env": "^10.1.0",
+    "esbuild": "^0.25.12",
     "jsdom": "^27.4.0",
+    "nostr-tools": "^2.19.4",
     "postcss": "^8.5.6",
     "tailwindcss": "^3.4.19",
     "ws": "^8.19.0"