refactor(tree): remove unused Factory generic from multiproof system

[yongkangc]

Removes the unused Factory generic parameter from ParallelProof, MultiProofConfig, MultiProofTask, and related types. The generic only existed to carry ConsistentDbView<Factory> but was never accessed.

Closes #18932

[Copilot]

Pull Request Overview

This refactoring removes the unused Factory generic parameter from the multiproof system components. The generic was originally added to carry ConsistentDbView<Factory> but analysis showed it was never actually accessed in production code.

• Removes the Factory generic from ParallelProof, MultiProofConfig, MultiProofTask, and related types
• Simplifies the API by eliminating unnecessary generic type parameters
• Updates method signatures and removes phantom data fields that were only used to maintain generic constraints

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
crates/trie/parallel/src/proof.rs	Removes Factory generic from ParallelProof struct and impl blocks, removes phantom data field
crates/engine/tree/src/tree/payload_processor/multiproof.rs	Removes Factory generic from all multiproof-related structs and simplifies configuration creation
crates/engine/tree/src/tree/payload_processor/mod.rs	Updates method call to use simplified configuration creation without Factory generic

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[Copilot]

The documentation comment is outdated. The method now extracts/splits configuration from input rather than creating 'from' input, and it returns both a cleared TrieInput and the config.

Suggested change

	/// Creates a new state root config from the trie input.
	///
	/// This returns a cleared [`TrieInput`] so that we can reuse any allocated space in the
	/// [`TrieInput`].
	/// Extracts configuration from the given [`TrieInput`], splitting out the config and returning
	/// both a cleared [`TrieInput`] (for reuse of allocated space) and the extracted [`MultiProofConfig`].
	///
	/// This allows for efficient reuse of the input's allocated space and separates the configuration
	/// needed for multiproof computation.