feat(parser-react): handler resolution through props — 4-level chains (B1)

[officialCodeWork]

Summary

TRACKER Step 2.3 — failure mode B1, the second pillar of Phase 2. <button onClick={onSave}> where onSave is a prop means the real handler lives at a call site — possibly four components up. Per-file analysis stops dead at the prop boundary; the chain resolver doesn't.

The fixture chain, resolved

SaveButton  onClick={onSave}                    ← the event
  ↑ Toolbar      onSave={onSaveDraft}           ← renamed hop
  ↑ EditorPanel  onSaveDraft={() => onPersist()} ← inline-arrow wrap
  ↑ DraftEditor  onPersist={persistDraft}        ← the real handler
      persistDraft = () => fetch("/api/drafts", { method: "POST" })

⇒  event SaveButton.onClick --triggers--> POST /api/drafts

traceLineage(SaveButton) now reports /api/drafts — through three files it never touches directly.

Honesty guarantees

• Chains dead after 4 levels flag the event unresolved-prop-handler and emit nothing — the OrphanButton fixture (handler never passed) has a forbidden assertion against cross-chain endpoint bleed.
• Handled shapes: renamed props, props.X access, inline arrows wrapping prop calls, destructure defaults, function-declaration and arrow-const handlers.

Found by the fixture

Expression-bodied arrows (() => onPersist()) — the body is the CallExpression, and getDescendantsOfKind excludes the node itself, so the whole chain silently died at the wrap hop. Both body scans now include the body node.

Eval

• Scorecard: 119 pass / 0 fail / 0 xfail · precision 1.000 · recall 1.000 · match accuracy 1.000
• 80 unit tests (3 new: 4-level grounding, lineage reachability, orphan flagging)

Documentation

• TRACKER.md — 2.3 done, Status → 2.4

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