feat(apisix): add Cloudron package

- Implements Apache APISIX packaging for Cloudron platform.
- Includes Dockerfile, CloudronManifest.json, and start.sh.
- Configured to use Cloudron's etcd addon.

🤖 Generated with Gemini CLI
Co-Authored-By: Gemini <noreply@google.com>

CloudronPackages/APISIX/apisix-source/apisix/admin/plugin_metadata.lua

@@ -0,0 +1,83 @@
+--
+-- Licensed to the Apache Software Foundation (ASF) under one or more
+-- contributor license agreements.  See the NOTICE file distributed with
+-- this work for additional information regarding copyright ownership.
+-- The ASF licenses this file to You under the Apache License, Version 2.0
+-- (the "License"); you may not use this file except in compliance with
+-- the License.  You may obtain a copy of the License at
+--
+--     http://www.apache.org/licenses/LICENSE-2.0
+--
+-- Unless required by applicable law or agreed to in writing, software
+-- distributed under the License is distributed on an "AS IS" BASIS,
+-- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+-- See the License for the specific language governing permissions and
+-- limitations under the License.
+--
+local pcall   = pcall
+local require = require
+local core    = require("apisix.core")
+local resource = require("apisix.admin.resource")
+local encrypt_conf = require("apisix.plugin").encrypt_conf
+
+local injected_mark = "injected metadata_schema"
+
+
+local function validate_plugin(name)
+    local pkg_name = "apisix.plugins." .. name
+    local ok, plugin_object = pcall(require, pkg_name)
+    if ok then
+        return true, plugin_object
+    end
+
+    pkg_name = "apisix.stream.plugins." .. name
+    return pcall(require, pkg_name)
+end
+
+
+local function check_conf(plugin_name, conf)
+    if not plugin_name then
+        return nil, {error_msg = "missing plugin name"}
+    end
+
+    local ok, plugin_object = validate_plugin(plugin_name)
+    if not ok then
+        return nil, {error_msg = "invalid plugin name"}
+    end
+
+    if not plugin_object.metadata_schema then
+        plugin_object.metadata_schema = {
+            type = "object",
+            ['$comment'] = injected_mark,
+            properties = {},
+        }
+    end
+    local schema = plugin_object.metadata_schema
+
+    local ok, err
+    if schema['$comment'] == injected_mark
+      -- check_schema is not required. If missing, fallback to check schema directly
+      or not plugin_object.check_schema
+    then
+        ok, err = core.schema.check(schema, conf)
+    else
+        ok, err = plugin_object.check_schema(conf, core.schema.TYPE_METADATA)
+    end
+
+    encrypt_conf(plugin_name, conf, core.schema.TYPE_METADATA)
+
+    if not ok then
+        return nil, {error_msg = "invalid configuration: " .. err}
+    end
+
+    return plugin_name
+end
+
+
+return resource.new({
+    name = "plugin_metadata",
+    kind = "plugin_metadata",
+    schema = core.schema.plugin_metadata,
+    checker = check_conf,
+    unsupported_methods = {"post", "patch"}
+})