feat(traverse): add into_state and into_state_and_scoping methods to ReusableTraverseCtx

[coleleavitt]

Summary

Add methods to extract user state from ReusableTraverseCtx after traversal:

• into_state() - consumes ctx and returns just the user state
• into_state_and_scoping() - consumes ctx and returns both state and Scoping

Motivation

When implementing multi-pass AST transformations, passes often need to:

1. Accumulate state during traversal (e.g., detect patterns)
2. Extract that state after traversal
3. Pass accumulated state to subsequent passes

Currently, the only way to extract state is via unsafe fn unwrap(). These new methods provide a safe API for this common pattern.

Example Use Case

// Pass 1: Detect string arrays
let mut ctx = ReusableTraverseCtx::new(MyState::new(), scoping, &allocator);
traverse_mut_with_ctx(&mut pass1, &mut program, &mut ctx);

// Extract state for next pass
let mut state = ctx.into_state();
pass1.finalize(&mut state);

// Pass 2: Use accumulated state
let scoping = SemanticBuilder::new().build(&program).semantic.into_scoping();
let mut ctx = ReusableTraverseCtx::new(state, scoping, &allocator);
traverse_mut_with_ctx(&mut pass2, &mut program, &mut ctx);

Changes

• Added pub fn into_state(self) -> State
• Added pub fn into_state_and_scoping(self) -> (State, Scoping)

[codspeed-hq]

CodSpeed Performance Report

Merging this PR will not alter performance

_{Comparing coleleavitt:feat/traverse-ctx-into-state (4d5a794) with main (78fa1ba)¹}

Summary

✅ 38 untouched benchmarks
⏩ 7 skipped benchmarks²

Footnotes

1. No successful run was found on main (61091c1) during the generation of this report, so 78fa1ba was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

2. 7 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩