Snapshot the full Agentic Shepherd issue rendering fixture

Todo2026-08-21jp

package: jp_attachment_agentic_shepherdtype: task

renders_full_issue_fixture renders a complete user-visible Markdown document but checks selected substrings. Duplicated sections, broken ordering, leaked content, and formatting changes can pass.

Acceptance criteria:

• Replace the substring checks with one exact static output assertion or an accepted snapshot.
• Keep focused unit tests for individual rendering rules.
• Normalize only genuinely unstable fields before comparison.
• Verify the test fails when a section is duplicated, reordered, or rendered with incorrect indentation.