Move plugins to manifest, pin Docker version, add Makefile

- Add plugins.txt listing all plugins for reproducible installs
- Add Makefile with setup/start/stop/install-plugins targets
- Remove user/plugins/ from git tracking
- Pin Docker image to 1.7.49.5-ls244

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

plugins/email/vendor/doctrine/lexer/composer.json

@@ -1,56 +0,0 @@
-{
-    "name": "doctrine/lexer",
-    "description": "PHP Doctrine Lexer parser library that can be used in Top-Down, Recursive Descent Parsers.",
-    "license": "MIT",
-    "type": "library",
-    "keywords": [
-        "php",
-        "parser",
-        "lexer",
-        "annotations",
-        "docblock"
-    ],
-    "authors": [
-        {
-            "name": "Guilherme Blanco",
-            "email": "guilhermeblanco@gmail.com"
-        },
-        {
-            "name": "Roman Borschel",
-            "email": "roman@code-factory.org"
-        },
-        {
-            "name": "Johannes Schmitt",
-            "email": "schmittjoh@gmail.com"
-        }
-    ],
-    "homepage": "https://www.doctrine-project.org/projects/lexer.html",
-    "require": {
-        "php": "^7.1 || ^8.0",
-        "doctrine/deprecations": "^1.0"
-    },
-    "require-dev": {
-        "doctrine/coding-standard": "^9 || ^12",
-        "phpstan/phpstan": "^1.3",
-        "phpunit/phpunit": "^7.5 || ^8.5 || ^9.6",
-        "psalm/plugin-phpunit": "^0.18.3",
-        "vimeo/psalm": "^4.11 || ^5.21"
-    },
-    "autoload": {
-        "psr-4": {
-            "Doctrine\\Common\\Lexer\\": "src"
-        }
-    },
-    "autoload-dev": {
-        "psr-4": {
-            "Doctrine\\Tests\\Common\\Lexer\\": "tests"
-        }
-    },
-    "config": {
-        "allow-plugins": {
-            "composer/package-versions-deprecated": true,
-            "dealerdirect/phpcodesniffer-composer-installer": true
-        },
-        "sort-packages": true
-    }
-}