Unicode-aware byte scanner using starts-with?/consume! for multi-byte APL glyphs. Handles numbers (¯-negative), string literals, identifiers (⎕ system names), all APL function/operator glyphs, :Keywords, comments ⍝, diamond ⋄, assignment ←. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>