chore(deps): remove unused direct lodash dependency

lodash was a direct dependency pinned to 4.18.1 but is not imported anywhere
in src/. It remains available transitively (slate-react/slate-dom/inquirer/
commitizen depend on it), so removing the direct declaration changes nothing
at runtime — it just drops an unused, oddly-pinned direct dep. (The audit's
"non-existent version" claim was a false positive: 4.18.1 resolves from the
registry with a valid integrity hash and loads correctly.)

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

package.json

@@ -78,7 +78,6 @@
     "jotai": "2.20.0",
     "linkify-react": "4.3.3",
     "linkifyjs": "4.3.3",
-    "lodash": "4.18.1",
     "matrix-js-sdk": "41.6.0-rc.0",
     "matrix-widget-api": "1.17.0",
     "millify": "6.1.0",