Normalize REST runtime action evidence

[chubes4]

Summary

• Normalizes rest_request runtime action observations into first-class REST evidence: method, path/route, status, headers, body, timing, and diagnostics.
• Extends the wordpress.rest-request command output with body/timing/diagnostics while preserving the existing data field.
• Tightens the focused REST runtime smoke coverage for direct command execution and action-adapter observations.

Closes #457.

Verification

• npm run build
• npm run build && npm run rest-request-runtime-smoke
• npm run command-registry-smoke
• npm run runtime-action-adapter-smoke
• git diff --check

AI assistance

• AI assistance: Yes
• Tool(s): OpenCode (openai/gpt-5.5)
• Used for: Implemented the normalized REST runtime action evidence and smoke assertions; Chris remains responsible for review and testing.