feat: add S3-compatible storage provider (MinIO, Ceph, R2, etc.)

Adds a new 'S3-Compatible Storage' provider that works with any
S3-API-compatible object storage service, including MinIO, Ceph,
Cloudflare R2, Backblaze B2, and others.

Changes:
- New provider class: classes/providers/storage/s3-compatible-provider.php
  - Provider key: s3compatible
  - Reads user-configured endpoint URL from settings
  - Uses path-style URL access (required by most S3-compatible services)
  - Supports credentials via AS3CF_S3COMPAT_ACCESS_KEY_ID /
    AS3CF_S3COMPAT_SECRET_ACCESS_KEY wp-config.php constants
  - Disables AWS-specific features (Block Public Access, Object Ownership)
- New provider SVG icons (s3compatible.svg, -link.svg, -round.svg)
- Registered provider in main plugin class with endpoint setting support
- Updated StorageProviderSubPage to show endpoint URL input for S3-compatible
- Built pro settings bundle with rollup (Svelte 4.2.19)
- Added package.json and updated rollup.config.mjs for pro-only builds

vendor/Aws3/Aws/Api/Parser/JsonParser.php

@@ -0,0 +1,57 @@
+<?php
+
+namespace DeliciousBrains\WP_Offload_Media\Aws3\Aws\Api\Parser;
+
+use DeliciousBrains\WP_Offload_Media\Aws3\Aws\Api\DateTimeResult;
+use DeliciousBrains\WP_Offload_Media\Aws3\Aws\Api\Shape;
+/**
+ * @internal Implements standard JSON parsing.
+ */
+class JsonParser
+{
+    public function parse(Shape $shape, $value)
+    {
+        if ($value === null) {
+            return $value;
+        }
+        switch ($shape['type']) {
+            case 'structure':
+                if (isset($shape['document']) && $shape['document']) {
+                    return $value;
+                }
+                $target = [];
+                foreach ($shape->getMembers() as $name => $member) {
+                    $locationName = $member['locationName'] ?: $name;
+                    if (isset($value[$locationName])) {
+                        $target[$name] = $this->parse($member, $value[$locationName]);
+                    }
+                }
+                if (isset($shape['union']) && $shape['union'] && \is_array($value) && empty($target)) {
+                    foreach ($value as $key => $val) {
+                        $target['Unknown'][$key] = $val;
+                    }
+                }
+                return $target;
+            case 'list':
+                $member = $shape->getMember();
+                $target = [];
+                foreach ($value as $v) {
+                    $target[] = $this->parse($member, $v);
+                }
+                return $target;
+            case 'map':
+                $values = $shape->getValue();
+                $target = [];
+                foreach ($value as $k => $v) {
+                    $target[$k] = $this->parse($values, $v);
+                }
+                return $target;
+            case 'timestamp':
+                return DateTimeResult::fromTimestamp($value, !empty($shape['timestampFormat']) ? $shape['timestampFormat'] : null);
+            case 'blob':
+                return \base64_decode($value);
+            default:
+                return $value;
+        }
+    }
+}