Attack activities should repath when projectiles are blocked from the target.

This combines the older tickets about actors moving to a new location if their projectiles are blocked from reaching their target by walls or terrain.

Checking if a projectile will be able to hit before it fires each time wouldn't be great on performance, so we should start hy implementing new plumbing to notify AttackBase (and maybe other traits) after a projectile is blocked by actors or terrain. The attack traits can then check for this case and trigger a repath.

Finding a cell to move too should be relatively easy: follow the approach of FindResources.ClosestHarvestablePos, replacing the "can harvest cell" check with a "can fire from" check:

• Use BlocksProjectiles.AnyBlockingActorsBetween for walls or other blocking actors.
• Terrain (on heightmap enabled mods) is slightly trickier, but could be split into phases (are there any height changes? → does the line intercept with a bounding box defiend by map.Height[cell]? → check points on path across cell).

See the comment below for a simpler approach

Start by reading the issue's follow-up comment and the older tickets it combines. Trace AttackBase, attack activities, and the projectile-blocking behavior, including BlocksProjectiles.AnyBlockingActorsBetween and FindResources.ClosestHarvestablePos. Done means blocked projectiles cause the relevant attack activity to repath toward a valid firing position without introducing unnecessary per-shot performance costs.