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>

phpunit.xml

@@ -21,18 +21,18 @@
         </include>
     </source>
     <php>
-        <env name="APP_ENV" value="testing"/>
-        <env name="APP_MAINTENANCE_DRIVER" value="file"/>
-        <env name="BCRYPT_ROUNDS" value="4"/>
-        <env name="BROADCAST_CONNECTION" value="null"/>
-        <env name="CACHE_STORE" value="array"/>
-        <env name="DB_CONNECTION" value="sqlite"/>
-        <env name="DB_DATABASE" value=":memory:"/>
-        <env name="MAIL_MAILER" value="array"/>
-        <env name="QUEUE_CONNECTION" value="sync"/>
-        <env name="SESSION_DRIVER" value="array"/>
-        <env name="PULSE_ENABLED" value="false"/>
-        <env name="TELESCOPE_ENABLED" value="false"/>
-        <env name="NIGHTWATCH_ENABLED" value="false"/>
+        <server name="APP_ENV" value="testing" force="true"/>
+        <server name="APP_MAINTENANCE_DRIVER" value="file" force="true"/>
+        <server name="BCRYPT_ROUNDS" value="4" force="true"/>
+        <server name="BROADCAST_CONNECTION" value="null" force="true"/>
+        <server name="CACHE_STORE" value="array" force="true"/>
+        <server name="DB_CONNECTION" value="sqlite" force="true"/>
+        <server name="DB_DATABASE" value=":memory:" force="true"/>
+        <server name="MAIL_MAILER" value="array" force="true"/>
+        <server name="QUEUE_CONNECTION" value="sync" force="true"/>
+        <server name="SESSION_DRIVER" value="array" force="true"/>
+        <server name="PULSE_ENABLED" value="false" force="true"/>
+        <server name="TELESCOPE_ENABLED" value="false" force="true"/>
+        <server name="NIGHTWATCH_ENABLED" value="false" force="true"/>
     </php>
 </phpunit>