I have modernized the BigDump script, refactoring it into a modern PHP application.

I've converted the original `bigdump.php` script into an object-oriented application with a clear separation of concerns.

Key changes include:
- A new directory structure (`src`, `public`, `templates`, `config`).
- Object-oriented code with classes for `Configuration`, `Database`, `FileHandler`, and `Dumper`.
- Separation of HTML, CSS, and JavaScript from the PHP logic.
- Improved security by mitigating XSS and file path traversal risks.
- A new `README.md` with updated instructions.
- Unit tests for the core classes (written but not run due to environment constraints).

tests/FileHandlerTest.php

@@ -0,0 +1,50 @@
+<?php
+
+use BigDump\Configuration;
+use BigDump\FileHandler;
+use PHPUnit\Framework\TestCase;
+
+class FileHandlerTest extends TestCase
+{
+    private $config;
+    private $fileHandler;
+    private $testFile;
+    private $uploadDir;
+
+    protected function setUp(): void
+    {
+        $this->config = new Configuration();
+        $this->fileHandler = new FileHandler($this->config);
+        $this->uploadDir = $this->config->upload_dir;
+        $this->testFile = $this->uploadDir . '/test.sql';
+
+        if (!is_dir($this->uploadDir)) {
+            mkdir($this->uploadDir, 0777, true);
+        }
+        file_put_contents($this->testFile, 'test data');
+    }
+
+    protected function tearDown(): void
+    {
+        if (file_exists($this->testFile)) {
+            unlink($this->testFile);
+        }
+        // Small cleanup: remove data dir if empty
+        if (is_dir($this->uploadDir) && count(scandir($this->uploadDir)) == 2) {
+            rmdir($this->uploadDir);
+        }
+    }
+
+    public function testGetAvailableDumps()
+    {
+        $dumps = $this->fileHandler->getAvailableDumps();
+        $this->assertCount(1, $dumps);
+        $this->assertEquals('test.sql', $dumps[0]['name']);
+    }
+
+    public function testDeleteFile()
+    {
+        $this->fileHandler->deleteFile('test.sql');
+        $this->assertFileDoesNotExist($this->testFile);
+    }
+}