Document structural patch ops in README, /help, and MCP guidance

[justguy]

Tracker task: t12
Tracker: llm-tracker
Swimlane: improvements
Priority: p2

Goal

Update the public contract so agents know the exact structural op shapes, hub-owned fields, conflict modes, and retry strategy for patch-driven board maintenance.

Current note

Keep README.md, workspace-template/README.md, MCP prompts, and agent guidance aligned with the structural patch contract.

Dependencies

• t8
• t11

Tracker context

• Created from the live llm-tracker improvements swimlane backlog.
• Keep the tracker row and the GitHub issue aligned as this work evolves.