fix(build): postinstall script patches flowbite-svelte TypeScript optional params

flowbite-svelte ships TypeScript optional-param syntax (x?: string, event?: MouseEvent,
date?: Date) in its dist .svelte files. Vite's esbuild dep pre-bundler processes these
files (via dist/*/index.js re-exports) and fails with "Unexpected '?'" parse errors
whenever the lockfile changes and the dep cache is rebuilt.

- Add scripts/postinstall.mjs: patches 4 specific TypeScript signatures in
  CommandPalette.svelte, ScrollSpy.svelte, and Datepicker.svelte after every npm install.
  Patches are idempotent and targeted — only the ?-in-param-position syntax is removed;
  optional-chaining (?.) in function bodies is untouched.
- Add "postinstall" script to package.json to run it automatically.
- Upgrade flowbite-svelte 1.31.0 → 1.33.1 (both have the same issue; 1.33.1 is current).
- npm update now works without breaking the dev server.

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

package.json

@@ -21,7 +21,8 @@
         "build:docker:dev": "docker compose -f ../aether_container_env/docker-compose.yml build ae_app && docker compose -f ../aether_container_env/docker-compose.yml up -d ae_app",
         "compose:down": "docker compose -f ../aether_container_env/docker-compose.yml --profile database down",
         "deploy:remote:test": "ssh linode.oneskyit.com 'bash /srv/env/test_aether/deploy.sh test'",
-        "deploy:remote:prod": "ssh linode.oneskyit.com 'bash /srv/env/prod_aether/deploy.sh prod'"
+        "deploy:remote:prod": "ssh linode.oneskyit.com 'bash /srv/env/prod_aether/deploy.sh prod'",
+        "postinstall": "node scripts/postinstall.mjs"
     },
     "devDependencies": {
         "@eslint/js": "9.39.4",
@@ -108,7 +109,7 @@
         "@tailwindcss/vite": "^4.3.0",
         "dayjs": "^1.11.10",
         "dexie": "^4.0.0",
-        "flowbite-svelte": "1.31.0",
+        "flowbite-svelte": "1.33.1",
         "html5-qrcode": "^2.3.8",
         "marked": "17.0.6",
         "openai": "^6.10.0",