## Summary
Profiling with thousands of creatures in range of each other showed `BaseAI.IsInvalidFactionTarget` checking Ethereal Voyage and active Honor on every acquisition candidate and then calling `BaseCreature.IsEnemy`, which checked both again. This makes `IsEnemy` the single authority and removes the duplicate per-pair work.
## Changes
- **`BaseCreature.IsEnemy`**: the Ethereal Voyage check sat below the `m is not BaseCreature` early return, so it never reached players — the only mobiles that cast it. It is hoisted next to the Honor veto. `GetMaster()` was called three times per creature pair (inside `Ethics.Player.Find(m, true)` and twice at the bottom); it is now computed once.
- **`BaseAI.IsInvalidFactionTarget`**: reduced to `IsFriend` / `IsEnemy` / `CanBeHarmful`. The removed `Combatant != m` Honor exception was dead code — `IsEnemy` vetoed Honor unconditionally on the following line.
- **`Ethics.Player.Find`** / **`TransformationSpellHelper.GetContext`**: small simplifications on the same path.
## Behavior
- `ShouldAcquireOnApproach` and `OnAggressiveAction` only consult `IsEnemy`, so movement-triggered acquisition now respects Ethereal Voyage for players (previously a player under Ethereal Voyage walking past a monster was still acquired on approach).
- `BaseFactionGuard.IsEnemy` does not call base, so faction guards no longer skip honoring/voyaging enemy-faction players. Accepted: both mechanics describe monsters, not guards.
- `HealerAI`/`BerserkAI`/`PredatorAI` (`bFacFriend`) callers are unaffected — `IsFriend` already required a `BaseCreature`, so players were excluded before these checks ran. `MilitiaFighter`/`MilitiaCanoneer` return `false` for all players, so they are unaffected too.
## Testing
- `dotnet build` clean.
- Pure predicate reorder; no new tests.
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