feat(useColorMode): expose state to the ref, deprecated emitAuto

[Waleed-KH]

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⚠️ Slowing down new functions

Warning: Slowing down new functions

As the VueUse audience continues to grow, we have been inundated with an overwhelming number of feature requests and pull requests. As a result, maintaining the project has become increasingly challenging and has stretched our capacity to its limits. As such, in the near future, we may need to slow down our acceptance of new features and prioritize the stability and quality of existing functions. Please note that new features for VueUse may not be accepted at this time. If you have any new ideas, we suggest that you first incorporate them into your own codebase, iterate on them to suit your needs, and assess their generalizability. If you strongly believe that your ideas are beneficial to the community, you may submit a pull request along with your use cases, and we would be happy to review and discuss them. Thank you for your understanding.

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Description

Applied some improvements was done in #2023

• Allow initialValue to be passed as ref
• Deprecated emitAuto, in favor of store.value when auto mode needs to be known
• Expose state, so dev won't need to write computed(() => store.value === 'auto' ? system.value : store.value) when extracting the store value
• Type improvements and fixes, this will help the dev to know exactly the values of store, system, state
• update useDark to use system.value instead of importing usePreferredDark

Additional context

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🤖 Generated by Copilot at f8e66e3

This pull request enhances the useColorMode function and its test case to provide better type safety, customization, and readability. It also removes some redundant code and improves the naming consistency.

🤖 Generated by Copilot at f8e66e3

• Introduce BasicColorMode type and constrain generic type parameter T to extend it (link, link, link, link)
• Change initialValue option to accept MaybeRef type and use it directly for store variable (link, link, link)
• Add state property to return value and use computed ref to return either store.value or state.value depending on emitAuto option (link, link)
• Simplify defaultOnChanged function and remove watch function for system value (link, link)
• Add deprecation notice to value property and link to documentation (link)
• Rename test case and variable to avoid confusion (packages/core/useColorMode/index.test.ts, link)