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/EnumValue.php

@@ -0,0 +1,123 @@
+<?php
+
+# Generated by the protocol buffer compiler.  DO NOT EDIT!
+# source: google/protobuf/type.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;
+/**
+ * Enum value definition.
+ *
+ * Generated from protobuf message <code>google.protobuf.EnumValue</code>
+ */
+class EnumValue extends \DeliciousBrains\WP_Offload_Media\Gcp\Google\Protobuf\Internal\Message
+{
+    /**
+     * Enum value name.
+     *
+     * Generated from protobuf field <code>string name = 1;</code>
+     */
+    protected $name = '';
+    /**
+     * Enum value number.
+     *
+     * Generated from protobuf field <code>int32 number = 2;</code>
+     */
+    protected $number = 0;
+    /**
+     * Protocol buffer options.
+     *
+     * Generated from protobuf field <code>repeated .google.protobuf.Option options = 3;</code>
+     */
+    private $options;
+    /**
+     * Constructor.
+     *
+     * @param array $data {
+     *     Optional. Data for populating the Message object.
+     *
+     *     @type string $name
+     *           Enum value name.
+     *     @type int $number
+     *           Enum value number.
+     *     @type array<\Google\Protobuf\Option>|\Google\Protobuf\Internal\RepeatedField $options
+     *           Protocol buffer options.
+     * }
+     */
+    public function __construct($data = NULL)
+    {
+        \DeliciousBrains\WP_Offload_Media\Gcp\GPBMetadata\Google\Protobuf\Type::initOnce();
+        parent::__construct($data);
+    }
+    /**
+     * Enum value name.
+     *
+     * Generated from protobuf field <code>string name = 1;</code>
+     * @return string
+     */
+    public function getName()
+    {
+        return $this->name;
+    }
+    /**
+     * Enum value name.
+     *
+     * Generated from protobuf field <code>string name = 1;</code>
+     * @param string $var
+     * @return $this
+     */
+    public function setName($var)
+    {
+        GPBUtil::checkString($var, True);
+        $this->name = $var;
+        return $this;
+    }
+    /**
+     * Enum value number.
+     *
+     * Generated from protobuf field <code>int32 number = 2;</code>
+     * @return int
+     */
+    public function getNumber()
+    {
+        return $this->number;
+    }
+    /**
+     * Enum value number.
+     *
+     * Generated from protobuf field <code>int32 number = 2;</code>
+     * @param int $var
+     * @return $this
+     */
+    public function setNumber($var)
+    {
+        GPBUtil::checkInt32($var);
+        $this->number = $var;
+        return $this;
+    }
+    /**
+     * Protocol buffer options.
+     *
+     * Generated from protobuf field <code>repeated .google.protobuf.Option options = 3;</code>
+     * @return \Google\Protobuf\Internal\RepeatedField
+     */
+    public function getOptions()
+    {
+        return $this->options;
+    }
+    /**
+     * Protocol buffer options.
+     *
+     * Generated from protobuf field <code>repeated .google.protobuf.Option options = 3;</code>
+     * @param array<\Google\Protobuf\Option>|\Google\Protobuf\Internal\RepeatedField $var
+     * @return $this
+     */
+    public function setOptions($var)
+    {
+        $arr = GPBUtil::checkRepeatedField($var, \DeliciousBrains\WP_Offload_Media\Gcp\Google\Protobuf\Internal\GPBType::MESSAGE, \DeliciousBrains\WP_Offload_Media\Gcp\Google\Protobuf\Option::class);
+        $this->options = $arr;
+        return $this;
+    }
+}