Direct binary precedence parsing

Date: 2026-04-29 Area: parser

Binary-expression precedence parsing now uses direct Peek.TokenType loops on the measured hot precedence layers instead of routing through the generic open-array ParseBinaryExpression helper. Production timing showed 3.6-18.9% parser-phase improvements across larger synthetic parser maps and 6.3-14.3% improvements across existing benchmark-file parse medians; rejected alternatives included explicit Advance inline, eager source-text removal, and repeated-Check(...) loops. spikes/parser-binary-expression-performance.md.