docs(plan): Phase L.3.1+L.3.2 PositionManager + retail-faithful jump plan
6-task plan with subagent dispatch on Tasks 1, 3, 5:
- Task 1: PositionManager class + 6 unit tests (subagent)
- Task 2: Plumb IsGrounded through EntityPositionUpdate (parent, ~5 lines)
- Task 3: Retail-faithful per-frame remote tick (subagent — biggest:
RemoteMotion.Position field + OnLivePositionUpdated rewrite [airborne
no-op + landing transition + grounded routing] + TickAnimations rewrite
[PositionManager.ComputeOffset + UpdatePhysicsInternal])
- Task 4: USER GATE (visual verification with retail observer)
- Task 5: Cleanup commit (subagent, parallel with 6)
- Task 6: Roadmap + spec status update (parent, parallel with 5)
Each task has TDD-style steps with exact file paths, code blocks, and
commit messages. Spec at c4446e7 lists L.3.1's already-shipped 6 commits;
this plan picks up from the revert at 1641d6e.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>