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/Gcp/google/protobuf/src/Google/Protobuf/DoubleValue.php

@@ -0,0 +1,62 @@
+<?php
+
+# Generated by the protocol buffer compiler.  DO NOT EDIT!
+# source: google/protobuf/wrappers.proto
+namespace DeliciousBrains\WP_Offload_Media\Gcp\Google\Protobuf;
+
+use DeliciousBrains\WP_Offload_Media\Gcp\Google\Protobuf\Internal\GPBType;
+use DeliciousBrains\WP_Offload_Media\Gcp\Google\Protobuf\Internal\RepeatedField;
+use DeliciousBrains\WP_Offload_Media\Gcp\Google\Protobuf\Internal\GPBUtil;
+/**
+ * Wrapper message for `double`.
+ * The JSON representation for `DoubleValue` is JSON number.
+ *
+ * Generated from protobuf message <code>google.protobuf.DoubleValue</code>
+ */
+class DoubleValue extends \DeliciousBrains\WP_Offload_Media\Gcp\Google\Protobuf\Internal\Message
+{
+    /**
+     * The double value.
+     *
+     * Generated from protobuf field <code>double value = 1;</code>
+     */
+    protected $value = 0.0;
+    /**
+     * Constructor.
+     *
+     * @param array $data {
+     *     Optional. Data for populating the Message object.
+     *
+     *     @type float $value
+     *           The double value.
+     * }
+     */
+    public function __construct($data = NULL)
+    {
+        \DeliciousBrains\WP_Offload_Media\Gcp\GPBMetadata\Google\Protobuf\Wrappers::initOnce();
+        parent::__construct($data);
+    }
+    /**
+     * The double value.
+     *
+     * Generated from protobuf field <code>double value = 1;</code>
+     * @return float
+     */
+    public function getValue()
+    {
+        return $this->value;
+    }
+    /**
+     * The double value.
+     *
+     * Generated from protobuf field <code>double value = 1;</code>
+     * @param float $var
+     * @return $this
+     */
+    public function setValue($var)
+    {
+        GPBUtil::checkDouble($var);
+        $this->value = $var;
+        return $this;
+    }
+}