## MODIFIED Requirements

### Requirement: Authoritative correction prunes acknowledged prediction history
The client sync strategy SHALL reconcile local prediction against authoritative player-state updates by pruning acknowledged movement inputs at or before the authoritative acknowledged movement tick and only reapplying newer pending `MoveInput` messages. For the controlled player, reconciliation MUST classify authoritative error after replay into a bounded-correction path for small cadence-aligned divergence and an immediate snap path for large divergence. When bounded correction is already active, later authoritative snapshots MUST deterministically replace, fold into, or escalate that correction based on the newest residual error instead of stacking unbounded visual offsets.

#### Scenario: Reconciliation removes already acknowledged movement inputs
- **WHEN** the client accepts an authoritative `PlayerState` update that acknowledges movement tick `N`
- **THEN** locally buffered predicted `MoveInput` messages with tick less than or equal to `N` are removed from the replay buffer
- **THEN** only `MoveInput` messages newer than `N` remain eligible for re-simulation

#### Scenario: Small post-replay error uses bounded correction
- **WHEN** the controlled client finishes replay after accepting an authoritative `PlayerState` and the remaining position or rotation error stays within the configured bounded-correction threshold
- **THEN** the client keeps authoritative ownership of the accepted snapshot
- **THEN** local presentation converges through bounded correction instead of an immediate hard snap on that frame

#### Scenario: New small error updates active bounded correction
- **WHEN** the controlled client accepts another authoritative `PlayerState` before the previous bounded correction has finished and the new residual error still stays within bounded-correction limits
- **THEN** the sync strategy updates the active bounded correction state using the newest authoritative residual error
- **THEN** the client does not queue multiple independent correction tails for the same controlled player

#### Scenario: Failed bounded correction escalates to snap
- **WHEN** the controlled client detects that the residual error from consecutive authoritative updates exceeds the snap threshold or remains non-convergent beyond the configured correction budget
- **THEN** the client immediately applies the authoritative transform state
- **THEN** any active bounded correction state is discarded before later prediction continues from the authoritative baseline