Refactored immutable structs into record types.

[lextatic]

Refactored several immutable structs into record types, significantly reducing boilerplate code.

Applied minor optimizations while ensuring no changes to existing functionality.

[Copilot]

Pull Request Overview

This PR refactors several immutable struct types to use C# record syntax, significantly reducing boilerplate code while maintaining the same functionality. The changes focus on eliminating manual implementations of equality operators, hash code generation, and property definitions.

• Converted 20+ struct types to record struct types with auto-implemented properties and equality
• Added compatibility support for .NET Standard 2.1 through IsExternalInit class
• Updated property access patterns to match the new positional parameter naming

Reviewed Changes

Copilot reviewed 33 out of 33 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
Forge/Effects/Stacking/StackingData.cs	Converted to record struct, removed manual equality/hash implementations
Forge/Effects/Periodic/PeriodicData.cs	Converted to record struct, simplified to single-line declaration
Forge/Effects/Modifiers/Modifier.cs	Converted to record struct, removed boilerplate code
Forge/Effects/ModifierEvaluatedData.cs	Converted struct to record struct
Forge/Effects/Magnitudes/*.cs	Multiple magnitude types converted to record structs
Forge/Effects/Duration/DurationData.cs	Converted to record struct with updated property name
Forge/Effects/ActiveEffect.cs	Updated property access to use new naming (AttributeOverride.Value)
Forge/Attributes/*.cs	Converted attribute-related structs to records and optimized EntityAttribute
Forge/Compatibility/IsExternalInit.cs	Added compatibility support for .NET Standard 2.1
Multiple test files	Updated constructor calls to use new positional parameter names

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