Cut over-engineering found by a repo-wide audit

- Config: auth, services, logging, queue and database only repeated the
  framework's own files and are gone; the others keep only the keys that
  differ (app version, cache serializable_classes, session cookie name,
  Markdown mail theme, the shares disk, three Octane values, Livewire's
  pagination theme and payload guards).
- Email verification is removed: User never implemented MustVerifyEmail,
  so it was never enforced, and SealShare has a single admin and no
  registration. CreateNewUser goes with it.
- FileEncryptionService::encryptFile() and generateSalt() were only used
  by tests; tests build files with encryptTestFile() in tests/Pest.php.
- The expiration options are defined once, as Share::EXPIRATIONS. "30 Days"
  now lasts 30 days instead of a calendar month, and Admin settings only
  save a default expiration that is one of the options.
- One-caller helpers are inlined, the uploader reads chunk responses with
  XHR's responseType, and starter-kit leftovers are removed.
- Docker: PHP reads the PHP_* limits from the environment itself
  (${VAR:-default} in uploads.ini); both entrypoints stop writing the ini.
  docker-compose.yml shares the app and scheduler variables through one
  anchor. The dev image installs gd for the screenshot publisher and fake
  test images.
- Development runs in Docker only: the composer dev script, concurrently,
  laravel/pail, laravel/sail, autoprefixer and the shell-quote override
  are gone.
- phpunit.xml forces the test environment with <server> entries, so tests
  run in the dev container no longer use its real database.

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

composer.json

@@ -22,9 +22,7 @@
     "require-dev": {
         "fakerphp/faker": "^1.23",
         "laravel/boost": "^2.0",
-        "laravel/pail": "^1.2.2",
         "laravel/pint": "^1.24",
-        "laravel/sail": "^1.41",
         "mockery/mockery": "^1.6",
         "nunomaduro/collision": "^8.6",
         "pestphp/pest": "^5.1",
@@ -52,10 +50,6 @@
             "npm install",
             "npm run build"
         ],
-        "dev": [
-            "Composer\\Config::disableProcessTimeout",
-            "npx concurrently -c \"#93c5fd,#c4b5fd,#fb7185,#fdba74\" \"php artisan octane:frankenphp --host=127.0.0.1 --port=8000 --watch\" \"php artisan queue:listen --tries=1 --timeout=0\" \"php artisan pail --timeout=0\" \"npm run dev\" --names=server,queue,logs,vite --kill-others"
-        ],
         "lint": [
             "pint --parallel"
         ],