Optimizations from server profile (#38290)

* Properly cache regexes in chat sanitization/accents

Wow I wonder if `new Regex()` has a cost to it *looks at server profile*.

* Avoid lag caused by Tippy command completions

CompletionHelper.PrototypeIDs explicitly says *not* to use it with EntityPrototype. Unsurprisingly, reporting a completion result for every entity prototype in the game is a *bad idea*.

* Add active count metrics to some high-load systems

Mover & NPCs

I suspect the thing that caused the Leviathan round to shit itself on performance is NPC spam in space or something. So let's verify that.

* Enable parallel processing on pow3r again

Originally disabled due to a theory of it causing bugs, it was re-enabled on Vulture, and I'm not aware of it having caused any issues there.

* Replace hashset with bitflags for AtmosMonitor alert types.

Allocating these hashsets was like 20% of the CPU of atmos, somehow.

* Cache HashSet used for space movement collider checks

Turns out this was a ton of server allocations. Huh.

Content.Server/Physics/Controllers/MoverController.cs

@@ -7,6 +7,7 @@ using Content.Shared.Movement.Components;
 using Content.Shared.Movement.Systems;
 using Content.Shared.Shuttles.Components;
 using Content.Shared.Shuttles.Systems;
+using Prometheus;
 using Robust.Shared.Physics.Components;
 using Robust.Shared.Player;
 using DroneConsoleComponent = Content.Server.Shuttles.DroneConsoleComponent;
@@ -17,6 +18,10 @@ namespace Content.Server.Physics.Controllers;
 
 public sealed class MoverController : SharedMoverController
 {
+    private static readonly Gauge ActiveMoverGauge = Metrics.CreateGauge(
+        "physics_active_mover_count",
+        "Active amount of InputMovers being processed by MoverController");
+
     [Dependency] private readonly ThrusterSystem _thruster = default!;
     [Dependency] private readonly SharedTransformSystem _xformSystem = default!;
 
@@ -97,6 +102,8 @@ public sealed class MoverController : SharedMoverController
             HandleMobMovement(mover, frameTime);
         }
 
+        ActiveMoverGauge.Set(_movers.Count);
+
         HandleShuttleMovement(frameTime);
     }