Why: The approved r0.3 plan must run against the current project member and IAM mainline.
Evidence: First task-sync conflict receipt was imported; Backend full Go tests and Frontend test/build passed after resolving component interactions; git diff --cached --check passed.
Impact: Combine current main with the existing U3 draft, preserving both planning entries and the Backend private project event proof transaction.
Refs: Dev PR #512; Backend PR #193; Frontend PR #79; Documents PR #95