Materialize trigger collections to eliminate ConcatIterator CPU waste

[PhenX]

…r CPU waste

Replace IEnumerable fields with List to avoid deeply nested ConcatIterator chains from repeated .Concat() calls. Each WithAdditionalTrigger call now uses List.Add() instead. Also cache the service provider hash code, use O(1) List.Count property instead of LINQ .Count(), and add count-based fast paths in ShouldUseSameServiceProvider to short-circuit before SequenceEqual.

(cherry picked from commit 0cc6aa1)

[Copilot]

Pull request overview

This PR optimizes TriggersOptionExtension to avoid CPU overhead from repeatedly chaining IEnumerable.Concat() (creating deep ConcatIterator trees) by materializing trigger collections into List<T>, and adds a couple of small fast paths around service-provider caching comparisons.

Changes:

• Replace trigger registries from IEnumerable<T> to List<T> and switch WithAdditional* methods to List.Add().
• Cache GetServiceProviderHashCode() result and use List.Count / count-based short-circuiting in ShouldUseSameServiceProvider().
• Avoid LINQ .Count() in debug info population.

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[Copilot]

Changing _triggers to List<...> means the public Triggers property now returns a reference to a mutable internal collection (it’s exposed as IEnumerable, but consumers can still cast back to List and mutate). That can invalidate the new GetServiceProviderHashCode() cache and break the expectation that option extensions are effectively immutable. Consider returning a read-only wrapper (AsReadOnly()), an IReadOnlyList, or otherwise preventing external mutation.

[Copilot]

_triggerTypes is non-nullable and always initialized in constructors, so clone._triggerTypes ??= new List<Type>(); is redundant and suggests the field can be null. Either remove the null-coalescing assignment here, or (if null is a valid state) make _triggerTypes nullable consistently and handle that throughout.

Suggested change

clone._triggerTypes ??= new List<Type>();