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/Speech/EntitySystems/ReplacementAccentSystem.cs

@@ -19,9 +19,21 @@ namespace Content.Server.Speech.EntitySystems
         [Dependency] private readonly IRobustRandom _random = default!;
         [Dependency] private readonly ILocalizationManager _loc = default!;
 
+        private readonly Dictionary<ProtoId<ReplacementAccentPrototype>, (Regex regex, string replacement)[]>
+            _cachedReplacements = new();
+
         public override void Initialize()
         {
             SubscribeLocalEvent<ReplacementAccentComponent, AccentGetEvent>(OnAccent);
+
+            _proto.PrototypesReloaded += OnPrototypesReloaded;
+        }
+
+        public override void Shutdown()
+        {
+            base.Shutdown();
+
+            _proto.PrototypesReloaded -= OnPrototypesReloaded;
         }
 
         private void OnAccent(EntityUid uid, ReplacementAccentComponent component, AccentGetEvent args)
@@ -48,27 +60,22 @@ namespace Content.Server.Speech.EntitySystems
                 return prototype.FullReplacements.Length != 0 ? Loc.GetString(_random.Pick(prototype.FullReplacements)) : "";
             }
 
-            if (prototype.WordReplacements == null)
-                return message;
-
             // Prohibition of repeated word replacements.
             // All replaced words placed in the final message are placed here as dashes (___) with the same length.
             // The regex search goes through this buffer message, from which the already replaced words are crossed out,
             // ensuring that the replaced words cannot be replaced again.
             var maskMessage = message;
 
-            foreach (var (first, replace) in prototype.WordReplacements)
+            foreach (var (regex, replace) in GetCachedReplacements(prototype))
             {
-                var f = _loc.GetString(first);
-                var r = _loc.GetString(replace);
                 // this is kind of slow but its not that bad
                 // essentially: go over all matches, try to match capitalization where possible, then replace
                 // rather than using regex.replace
-                for (int i = Regex.Count(maskMessage, $@"(?<!\w){f}(?!\w)", RegexOptions.IgnoreCase); i > 0; i--)
+                for (int i = regex.Count(maskMessage); i > 0; i--)
                 {
                     // fetch the match again as the character indices may have changed
-                    Match match = Regex.Match(maskMessage, $@"(?<!\w){f}(?!\w)", RegexOptions.IgnoreCase);
-                    var replacement = r;
+                    Match match = regex.Match(maskMessage);
+                    var replacement = replace;
 
                     // Intelligently replace capitalization
                     // two cases where we will do so:
@@ -98,5 +105,40 @@ namespace Content.Server.Speech.EntitySystems
 
             return message;
         }
+
+        private (Regex regex, string replacement)[] GetCachedReplacements(ReplacementAccentPrototype prototype)
+        {
+            if (!_cachedReplacements.TryGetValue(prototype.ID, out var replacements))
+            {
+                replacements = GenerateCachedReplacements(prototype);
+                _cachedReplacements.Add(prototype.ID, replacements);
+            }
+
+            return replacements;
+        }
+
+        private (Regex regex, string replacement)[] GenerateCachedReplacements(ReplacementAccentPrototype prototype)
+        {
+            if (prototype.WordReplacements is not { } replacements)
+                return [];
+
+            return replacements.Select(kv =>
+                {
+                    var (first, replace) = kv;
+                    var firstLoc = _loc.GetString(first);
+                    var replaceLoc = _loc.GetString(replace);
+
+                    var regex = new Regex($@"(?<!\w){firstLoc}(?!\w)", RegexOptions.IgnoreCase);
+
+                    return (regex, replaceLoc);
+
+                })
+                .ToArray();
+        }
+
+        private void OnPrototypesReloaded(PrototypesReloadedEventArgs obj)
+        {
+            _cachedReplacements.Clear();
+        }
     }
 }