Add Docker one-click deploy and data migration docs.

Enable PHP 8.2 + Apache compose stack with persistent data/uploads volumes and PhpSpreadsheet for xlsx import/export.

Co-authored-by: Cursor <cursoragent@cursor.com>

composer.json

@@ -0,0 +1,16 @@
+{
+  "name": "jinniu/loan-archive",
+  "description": "金牛集团贷款档案管理系统",
+  "type": "project",
+  "require": {
+    "php": ">=8.0",
+    "ext-pdo_sqlite": "*",
+    "ext-mbstring": "*",
+    "ext-fileinfo": "*",
+    "phpoffice/phpspreadsheet": "^1.29"
+  },
+  "config": {
+    "optimize-autoloader": true,
+    "sort-packages": true
+  }
+}