heredocDelimiter, executionRegion and scanShell each carried one long character loop with every quote, escape, heredoc, case and scope rule inline, which is where the three complexity warnings came from. The delimiter reader now has skipDelimiterBlanks, delimiterEscape and readDelimiterWord; the $(...) walker dispatches to regionQuotedEnd, regionSubstitution, openRegionQuote, regionHeredocOperator, regionHeredocBodies, casePhaseStep and closeRegionParen; and the top-level scanner keeps its position and pending word on a scan object that scanQuotedChar, scanEscape, scanSubstitution, openQuote, scanOperator and scanRedirect advance.
Every budget.spend call keeps its amount and order, so the work quota tests still land in the same window. The module still has no requires and exports createBudget, scanShell and scanExpansions unchanged; a differential run of the old and new scanner over the hook test corpus plus 58k generated inputs produced identical commands, nested regions and spend totals.
