Fixes the long-standing "monster loses track of a player who runs
around a corner" reports. Root causes and fixes:
1. Movement contract: MoveTo/ApproachTarget returned false on every
healthy mid-chase tick, so MeleeAI's inherited "move failed and
>RangePerception+1 -> Guard" clause (RunUO only ran it on real
blockage) fired every tick of every chase. They now report failure
only on genuine movement failure (no step with no working path, or
approach give-up). ArcherAI's equivalent clause moves to the hard
leash.
2. Last-known-position pursuit: while a combatant is in LOS its
position is recorded each think tick. When the target vanishes
(corner, hiding, recall) the creature investigates the last-seen
spot, stands guard there ~10s (restoring RunUO's guard grace that
had decayed to a single tick), and re-engages instantly if the same
target re-enters view - bypassing the 10s reacquire throttle.
3. ChaseLeashRange (virtual, default RangePerception * 2 = 32 tiles)
replaces the inline RangePerception * 3; per-creature tunable.
4. Group movement is now a crowding refinement, not a movement mode:
it only engages near the target when allies contest the ring, and
blocked/wall-slid steps escalate to the pathfinder instead of
reporting success - previously any creature with one ally on the
same target greedy-stepped for the whole chase and never pathfound.
5. Mages close distance when geometry (not hiding) blocks line of
sight instead of standing at a wall holding a spell until the 60s
combatant expiry.
6. Move budget: one actual step per AI think tick (half-step NextMove
charge). Code paths that attempted several moves in one tick could
cross multiple tiles at once - visible as "warping" when crowded
creatures jockey for position. Blocked attempts consume nothing, so
retry ladders are unaffected. CanMoveNow is wraparound-safe now.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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