use a custom tinymce svelte component and other minor optimizations

ui/package.json

@@ -25,7 +25,6 @@
     "@codemirror/state": "^6.0.0",
     "@codemirror/view": "^6.0.0",
     "@sveltejs/vite-plugin-svelte": "^2.4.1",
-    "@tinymce/tinymce-svelte": "^1.0.0",
     "chart.js": "^3.7.1",
     "chartjs-adapter-luxon": "^1.2.0",
     "luxon": "^2.3.2",