Name the npm package so the lock file stops flipping

Without a name, npm writes the folder's name into package-lock.json: "app" in
the dev container, "SealShare" on the host, so every install changed the file.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

package.json

@@ -1,5 +1,6 @@
 {
     "$schema": "https://www.schemastore.org/package.json",
+    "name": "sealshare",
     "private": true,
     "type": "module",
     "scripts": {