Route workflow inputs after JSON validation

Parse with a strict JSON implementation and reject duplicate keys, invalid control characters, excessive nesting and oversized values before branching. Syntax success should route a parsed value, not merely the original string, so downstream steps do not reinterpret it differently. Add schema and business-rule validation as separate stages. The invalid branch should carry a stable error code, bounded path or offset, and correlation identifier without echoing secrets or the full payload. Track accepted and rejected counts and cap diagnostic storage.