Consume the engine-owned sync plan

[callumalpass]

Summary

• replace plugin-owned sync preview policy with a direct projection of the engine-owned plan
• preserve structured conflicts and blocking issues without inventing transfer actions
• update the controlled consumer to exact beta.40 protocol/sync packages
• rebuild the committed Obsidian bundle from the registry artifacts

Verification

• npm test (42 tests)
• npm run build
• npm run check:mobile (602109 raw / 172187 gzip, both within budget)
• exact package-lock integrity for beta.40