Inline single-backtick spans and multi-line fenced ```blocks``` now
render with monospace styling as you type, plus real per-language
syntax highlighting for fenced blocks (reusing the existing
SyntaxHighlighter utility). Only complete, closed spans/fences light
up — an unterminated backtick or fence is left as plain text until
closed.
Pure regex/range logic extracted into testable static functions
(inlineCodeRanges, fencedCodeBlocks, fencedCodeBlockRanges) rather
than living inline in the NSTextView coordinator.
rune
0e4389d272