Move examples to server directory (#198)

* move examples to server directory

This will prepare for the client implementation in https://github.com/modelcontextprotocol/php-sdk/pull/192

* fix move bootstrap too

examples/env-variables/EnvToolHandler.php

@@ -1,51 +0,0 @@
-<?php
-
-/*
- * This file is part of the official PHP MCP SDK.
- *
- * A collaboration between Symfony and the PHP Foundation.
- *
- * For the full copyright and license information, please view the LICENSE
- * file that was distributed with this source code.
- */
-
-namespace Mcp\Example\EnvVariables;
-
-use Mcp\Capability\Attribute\McpTool;
-
-final class EnvToolHandler
-{
-    /**
-     * Performs an action that can be modified by an environment variable.
-     * The MCP client should set 'APP_MODE' in its 'env' config for this server.
-     *
-     * @param string $input some input data
-     *
-     * @return array<string, string|int> the result, varying by APP_MODE
-     */
-    #[McpTool(name: 'process_data_by_mode')]
-    public function processData(string $input): array
-    {
-        $appMode = getenv('APP_MODE'); // Read from environment
-
-        if ('debug' === $appMode) {
-            return [
-                'mode' => 'debug',
-                'processed_input' => strtoupper($input),
-                'message' => 'Processed in DEBUG mode.',
-            ];
-        } elseif ('production' === $appMode) {
-            return [
-                'mode' => 'production',
-                'processed_input_length' => \strlen($input),
-                'message' => 'Processed in PRODUCTION mode (summary only).',
-            ];
-        } else {
-            return [
-                'mode' => $appMode ?: 'default',
-                'original_input' => $input,
-                'message' => 'Processed in default mode (APP_MODE not recognized or not set).',
-            ];
-        }
-    }
-}