Allow keeping Atoms alive within a scope until it's deallocation

[ra1028]

Pull Request Type

• Bug fix
• New feature
• Refactoring
• Documentation update
• Chore

Issue for this PR

Link: #165

[Copilot]

Pull Request Overview

This PR adds support for retaining atoms for the lifetime of a view scope, introducing new scope tracking structures and updating cache/subscription management to use them.

• Replace initializedScope with scopeValues in AtomCache and adapt initializer calls.
• Add ScopeValues, ScopeState, and scopes in StoreState to track active scopes and unregister atoms when scopes deallocate.
• Update StoreContext to register/unregister scopes, use state.subscribed instead of the old graph field for subscriptions, and adjust related logic.
• Revise tests and documentation to reflect the new scope-based keep-alive behavior.

Reviewed Changes

Copilot reviewed 17 out of 17 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
Tests/AtomsTests/Utilities/Utilities.swift	Renamed initializer argument from initializedScope to scopeValues.
Tests/AtomsTests/Core/StoreContextTests.swift	Adjusted assertions to use store.state.subscribed.
Tests/AtomsTests/Core/ScopeKeyTests.swift	Added @MainActor to testDescription.
Tests/AtomsTests/Core/AtomCacheTests.swift	Updated test to use scopeValues in AtomCache initializer.
Tests/AtomsTests/Attribute/KeepAliveTests.swift	Expanded KeepAlive tests to cover scoped and overridden scopes.
Sources/Atoms/Core/StoreState.swift	Added subscribed and scopes dictionaries.
Sources/Atoms/Core/StoreContext.swift	Refactored to use ScopeValues, register/unregister scopes, and switch to state.subscribed.
Sources/Atoms/Core/ScopeValues.swift	Introduced ScopeValues to capture scope parameters.
Sources/Atoms/Core/ScopeState.swift	Added ScopeState class to automatically unregister on deinit.
Sources/Atoms/Core/ScopeKey.swift	Made Token actor-isolated with @MainActor.
Sources/Atoms/Core/Scope.swift	Reduced Scope to only track atom keys.
Sources/Atoms/Core/Graph.swift	Removed deprecated subscribed field.
Sources/Atoms/Core/AtomKey.swift	Exposed scopeKey to public, removed isScoped.
Sources/Atoms/Core/AtomCache.swift	Replaced initializedScope with scopeValues, added shouldKeepAlive.
Sources/Atoms/Attribute/KeepAlive.swift	Clarified documentation for scoped/override retention behavior.
Sources/Atoms/AtomScope.swift	Updated AtomScope to register new scopes via ScopeState.
README.md	Added scoped retention note under KeepAlive.

[Copilot]

The store property is missing its @Environment(\.store) property wrapper, so it will never be injected and will always be nil. It should be declared as @Environment(\.store) private var store.

[Copilot]

[nitpick] Registering a scope via side effects directly in the SwiftUI View body can lead to unpredictable behaviors. Consider moving registerScope to an onAppear modifier or the view initializer to avoid side effects during view recomputation.

Suggested change

	scopedStore?.registerScope(state: state.scopeState)
	return content.environment(\.store, scopedStore)
	return content
	.environment(\.store, scopedStore)
	.onAppear {
	scopedStore?.registerScope(state: state.scopeState)
	}