[Documentation] Add bilingual README and MeteorTest contract

[ConnorQi01]

Summary

Add an English primary README and a Simplified Chinese mirror for iOS-Automation-Framework, using a structure aligned with MeteorTest. This also updates the platform integration contract from test-platform.yml to meteortest.yml.

Proposed Changes

• Convert README.md to English as the primary README.
• Add README.zh-CN.md with aligned Simplified Chinese content.
• Rename test-platform.yml to meteortest.yml.
• Update docs/platform-integration.md to reference MeteorTest and meteortest.yml.
• Preserve the repository's API/UI/performance testing scope, local demo console guidance, and platform integration explanation.

Test Plan

• Documentation and contract rename only; no runtime tests were run.
• Ran git diff --check.
• Parsed meteortest.yml with PyYAML and confirmed project key yunlu-ios and 5 suites.

Closes #25