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/Atmos/Monitor/Systems/AtmosAlarmableSystem.cs

@@ -108,9 +108,9 @@ public sealed class AtmosAlarmableSystem : EntitySystem
                     break;
                 }
 
-                if (args.Data.TryGetValue(AlertTypes, out HashSet<AtmosMonitorThresholdType>? types) && component.MonitorAlertTypes != null)
+                if (args.Data.TryGetValue(AlertTypes, out AtmosMonitorThresholdTypeFlags types) && component.MonitorAlertTypes != AtmosMonitorThresholdTypeFlags.None)
                 {
-                    isValid = types.Any(type => component.MonitorAlertTypes.Contains(type));
+                    isValid = (types & component.MonitorAlertTypes) != 0;
                 }
 
                 if (!component.NetworkAlarmStates.ContainsKey(args.SenderAddress))