Changed uwf thread read to wrap role prompts and agent outputs in XML tags
(<prompt> and <output>) instead of markdown headings (### Prompt, ### Content).
This prevents Claude Code from treating step outputs as structural headings.
- Updated formatStepPrompt to use <prompt>...</prompt> tags
- Updated formatStepContent to use <output>...</output> tags
- Added comprehensive test suite in thread-read-xml-tags.test.ts
- Updated existing tests to verify XML tag behavior
Fixes#459
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>