Replace ZipStream with native ZipArchive for FrankenPHP compatibility

ZipStream writes via fwrite(php://output) which FrankenPHP silently
drops, resulting in 0-byte ZIP downloads. Switch to ZipArchive to build
the ZIP as a temp file on disk, then serve with response()->download().

- Rewrite download() to use ZipArchive + BinaryFileResponse
- Remove decryptFileToCallback() from FileEncryptionService
- Update tests for BinaryFileResponse instead of StreamedResponse
- Remove maennchen/zipstream-php dependency

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

composer.lock

@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "6b7f78bec30d422ca6805f3c503bd185",
+    "content-hash": "389e06b64c73b11ea3484bda4e3c5e21",
     "packages": [
         {
             "name": "bacon/bacon-qr-code",
@@ -2828,84 +2828,6 @@
             ],
             "time": "2026-02-09T22:59:54+00:00"
         },
-        {
-            "name": "maennchen/zipstream-php",
-            "version": "3.2.1",
-            "source": {
-                "type": "git",
-                "url": "https://github.com/maennchen/ZipStream-PHP.git",
-                "reference": "682f1098a8fddbaf43edac2306a691c7ad508ec5"
-            },
-            "dist": {
-                "type": "zip",
-                "url": "https://api.github.com/repos/maennchen/ZipStream-PHP/zipball/682f1098a8fddbaf43edac2306a691c7ad508ec5",
-                "reference": "682f1098a8fddbaf43edac2306a691c7ad508ec5",
-                "shasum": ""
-            },
-            "require": {
-                "ext-mbstring": "*",
-                "ext-zlib": "*",
-                "php-64bit": "^8.3"
-            },
-            "require-dev": {
-                "brianium/paratest": "^7.7",
-                "ext-zip": "*",
-                "friendsofphp/php-cs-fixer": "^3.86",
-                "guzzlehttp/guzzle": "^7.5",
-                "mikey179/vfsstream": "^1.6",
-                "php-coveralls/php-coveralls": "^2.5",
-                "phpunit/phpunit": "^12.0",
-                "vimeo/psalm": "^6.0"
-            },
-            "suggest": {
-                "guzzlehttp/psr7": "^2.4",
-                "psr/http-message": "^2.0"
-            },
-            "type": "library",
-            "autoload": {
-                "psr-4": {
-                    "ZipStream\\": "src/"
-                }
-            },
-            "notification-url": "https://packagist.org/downloads/",
-            "license": [
-                "MIT"
-            ],
-            "authors": [
-                {
-                    "name": "Paul Duncan",
-                    "email": "pabs@pablotron.org"
-                },
-                {
-                    "name": "Jonatan Männchen",
-                    "email": "jonatan@maennchen.ch"
-                },
-                {
-                    "name": "Jesse Donat",
-                    "email": "donatj@gmail.com"
-                },
-                {
-                    "name": "András Kolesár",
-                    "email": "kolesar@kolesar.hu"
-                }
-            ],
-            "description": "ZipStream is a library for dynamically streaming dynamic zip files from PHP without writing to the disk at all on the server.",
-            "keywords": [
-                "stream",
-                "zip"
-            ],
-            "support": {
-                "issues": "https://github.com/maennchen/ZipStream-PHP/issues",
-                "source": "https://github.com/maennchen/ZipStream-PHP/tree/3.2.1"
-            },
-            "funding": [
-                {
-                    "url": "https://github.com/maennchen",
-                    "type": "github"
-                }
-            ],
-            "time": "2025-12-10T09:58:31+00:00"
-        },
         {
             "name": "monolog/monolog",
             "version": "3.10.0",