fix(api-docs): restore full tag descriptions for API compatibility and Supported operations
Replace truncated "Overview of..." one-liners in tags.yml with proper
descriptions:
- API compatibility (Cloud Dedicated, Cloud Serverless, Clustered):
restore multi-paragraph descriptions from origin/master specs covering
write endpoints, query protocols, and v1/v2 compatibility. Move
external doc links to x-related.
- Supported operations (Cloud v2, OSS v2, Cloud Serverless): replace
with reference-style descriptions and HTTP method convention table.