(optimization): Using SyntaxNodeBuilder pattern for get_children

[eytan-starkware]

TL;DR

Optimize syntax node traversal by introducing a SyntaxNodeBuilder that delays node construction until needed.

What changed?

This PR introduces a new SyntaxNodeBuilder type that provides access to a child node's metadata without immediately constructing a full SyntaxNode. The key changes include:

• Modified ChildrenIter to return SyntaxNodeBuilder instead of SyntaxNode
• Added a .nodes(db) method to eagerly build syntax nodes when needed
• Updated all code that uses get_children(db) to either:
  • Use the new builder directly when only metadata is needed
  • Call .nodes(db) or .build(db) when a full syntax node is required
• Optimized collect_green_nodes to work directly with green nodes instead of constructing syntax nodes

[reviewable-StarkWare]

This change is 

[eytan-starkware]

Warning

This pull request is not mergeable via GitHub because a downstack PR is open. Once all requirements are satisfied, merge this PR as a stack on Graphite.
Learn more

• (optimization): Using SyntaxNodeBuilder pattern for get_children #8529 👈 (View in Graphite)
• Make get_children an iterator #8527
• Keeping SyntaNode's kind and parent kind for optimization #8515 : 1 other dependent PR (#8578 )
• Keeping SyntaxNode parent's data id for optimizations #8513
• Making Stable Syntax Pointers just a wrapper around syntax nodes #8501 : 1 other dependent PR (#8507 )
• Tracking SyntaxNode and interning through a tracked function #8489
• main

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[orizi]

@orizi reviewed all commit messages.
Reviewable status: 0 of 14 files reviewed, 2 unresolved discussions (waiting on @TomerStarkware)

---

crates/cairo-lang-syntax/src/node/mod.rs line 145 at r1 (raw file):

    /// Eagerly builds syntax nodes for the remaining children.
    pub fn nodes(

Suggestion:

pub fn as_syntax_nodes(

---

crates/cairo-lang-syntax/src/node/mod.rs line 193 at r1 (raw file):

    /// Constructs a [SyntaxNode] for this child.
    pub fn build(&self, db: &'a dyn Database) -> SyntaxNode<'a> {

Suggestion:

    pub fn as_syntax_node(&self, db: &'a dyn Database) -> SyntaxNode<'a> {

[TomerStarkware]

@TomerStarkware reviewed 14 of 14 files at r1, all commit messages.
Reviewable status: all files reviewed, 2 unresolved discussions (waiting on @eytan-starkware)