fix(config): exclude $schema from extra parameters sent to DNS APIs

[Copilot]

The $schema field from JSON config files was being passed to DNS provider APIs as an extra parameter, causing UnknownParameter errors in v4.1.1 (worked in v4.1.0).

Root Cause

$schema was not in the _known_keys set, so it was collected into the extra dict and unpacked via **extra when calling provider methods like _query_record() and _create_record().

Changes

• ddns/config/config.py: Added $schema to _known_keys set to exclude it from extra parameters
• tests/test_config_extra.py: Added test case to verify $schema exclusion

Example

Before fix, using this config:

{
  "$schema": "https://ddns.newfuture.cc/schema/v4.1.json",
  "dns": "tencentcloud",
  "extra": { "Remark": "DDNS" }
}

Would result in extra = {"$schema": "...", "Remark": "DDNS"} being sent to API.

After fix: extra = {"Remark": "DDNS"} (correct).

Original prompt

---

This section details on the original issue you should resolve

<issue_title>The parameter $schema is not recognized. (v4.1.1)</issue_title>
<issue_description>使用同样的配置文件，在4.1.0版本能正常运行，4.1.1版本报错
2025-11-03 14:49:52 ERROR [TencentCloudProvider]: TencentCloud API error: UnknownParameter - The parameter $schema is not recognized.</issue_description>

<agent_instructions>比较4.1.0和4.1.1相关的修改, 是否为 extra 参数带来的bug,并fix</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes The parameter $schema is not recognized. (v4.1.1) #575

---

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.

[Copilot]

Pull Request Overview

This PR prevents the $schema field from JSON configuration files from being collected as an extra field. The $schema field is a standard JSON Schema reference used for validation and IDE support, and should not be passed to DNS provider APIs.

• Added $schema to the set of known configuration keys that are filtered out from extra fields
• Added a comprehensive test to verify $schema is excluded while other extra fields are still collected

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated no comments.

File	Description
ddns/config/config.py	Added $schema to the _known_keys set to exclude it from extra field collection
tests/test_config_extra.py	Added test case to verify $schema field is properly excluded from extra fields