docs: correct the transports package description

[FanouZeng-TT]

Description

The README describes ucp_sdk.models.schemas.transports as containing REST,
MCP, and embedded protocol bindings:

REST, MCP, and embedded protocol bindings

The generated package has no REST module. Its current modules are
a2a_message, embedded_config, embedded_message, jsonrpc, and
mcp_tool_call, so the table both names a non-existent transport and omits A2A
and JSON-RPC.

Fix: describe the package as A2A, JSON-RPC, MCP, and embedded bindings,
matching its generated module set.

Category (Required)

• Core Protocol: Changes to the UCP protocol itself. (Requires Technical Council approval)
• Governance/Contributing: Changes to governance or contribution processes. (Requires Governance Council approval)
• Capability: Changes to an existing UCP capability. (Requires Maintainer approval)
• Documentation: Documentation-only changes. (Requires Maintainer approval)
• Infrastructure: Changes to CI/CD or infrastructure. (Requires DevOps Maintainer approval)
• Maintenance: Dependency updates or routine maintenance. (Requires DevOps Maintainer approval)
• SDK: Language-specific SDK updates and releases. (Requires DevOps Maintainer approval)
• Samples / Conformance: Maintaining samples and the conformance suite. (Requires Maintainer approval)
• UCP Schema: Changes to the ucp-schema tool. (Requires Maintainer approval)
• Community Health (.github): Changes to shared GitHub configuration. (Requires DevOps Maintainer approval)

Related Issues

N/A

Checklist

• I have followed the Contributing Guide and Code of Conduct.
• I have updated the documentation (if applicable).
• My changes pass all local linting and formatting checks.
• I have added tests that prove my fix is effective.
• New and existing unit tests pass locally with my changes.
• (For Core/Capability) I have included/updated the relevant JSON schemas.
• I have regenerated Python Pydantic models by running generate_models.sh under python_sdk.

Screenshots / Logs (if applicable)

• Verified the five generated transport modules: a2a_message,
  embedded_config, embedded_message, jsonrpc, and mcp_tool_call
• uvx pre-commit run --all-files — all hooks passed, including ShellCheck
• git diff --check — passed

🤖 Generated with Claude Code

[FanouZeng-TT]

Opened prematurely while preparing the next candidate. Closing immediately to preserve the repository contribution cadence; no maintainer action is needed.