Modernise codebase to C# 12 and fix formatting bugs

[jedrek0429]

• Reduced traditional constructors to primary constructors across models.
• Utilised secondary constructors (: this(...)) for classes with constructor overloads.
• Removed unnecessary private fields and traditional if checks in constructors in favour of pattern matching.
• Added using NetCord.JsonModels; or using NetCord.Rest.JsonModels; and simplified type references from JsonModels.X to X.
• Added missing XML documentation to all refactored classes and properties.
• Added IJsonModel implementation to InteractionResolvedData and Interaction.
• Removed deprecated Summary property from IntegrationApplication.
• Fixed an issue in InteractionResolvedData where Users mapping relied on dictionary iteration order matching GuildUsers, replacing manual enumerator iteration with safe TryGetValue lookups.
• Fixed field initialization order bugs in RestGuild where Id evaluated to 0 during Roles and Emojis dictionary initialization.
• Retained explicit constructors for Guild and RestGuild to support complex update/copy constructor logic.
• Retained explicit constructor for RestMessage and RestGuild to support complex constructor logic.
• Modernised Interaction class and optimised object factory.
• Retained explicit constructor for Interaction to support complex constructor logic.
• Modernised WebhookEventArgs by utilising constructor parameters, enforcing readonly encapsulation on event data fields, and aligning ApplicationDeauthorizedWebhookEventArgs with the authorization class structure.
• Retained explicit constructor for WebhookEventArgs to support complex constructor logic.
• Removed private protected readonly field _jsonModels from User, Webhook and ApplicationCommand.
• Removed private protected field _client from CustomEmoji.
• Removed private readonly field _client from GuildSticker.
• Refactored ApplicationCommandOption, CustomEmoji and ApplicationCommand string formatting to fix bugs and improve performance.
• Retained explicit constructor for GuildScheduledEventUser, MessageComponentInteraction and GuildScheduledEventUser to handle inline mutations.
  • Initialization requires an in-flight side effect mutation of the underlying jsonModel properties before child entities can be correctly instantiated. This could be refactored in a separate PR.