fix(deps): require PHP >=8.3 to match typed class constants

ContributionStore uses a typed class constant (PHP 8.3+), but composer.json
still allowed 8.2. PHPStan 2.3 reads the constraint and fails on it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

composer.json

@@ -4,7 +4,7 @@
     "type": "project",
     "license": "MIT",
     "require": {
-        "php": ">=8.2",
+        "php": ">=8.3",
         "monolog/monolog": "^3.10",
         "symfony/cache": "7.4.*",
         "symfony/console": "7.4.*",

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": "65e112e17f2cf3ba6ebccbbc3a0fcbfa",
+    "content-hash": "79811db631df6eb8fad05f9bb2caf385",
     "packages": [
         {
             "name": "monolog/monolog",
@@ -5079,7 +5079,7 @@
     "prefer-stable": false,
     "prefer-lowest": false,
     "platform": {
-        "php": ">=8.2"
+        "php": ">=8.3"
     },
     "platform-dev": {},
     "plugin-api-version": "2.9.0"