The workflowCost function had includeCompleted defaulting to true, but
the api-surface.md specifies the default should be false. Fixed the
default and updated test suite to verify the correct default behavior
and add explicit test for includeCompleted: true opt-in case.
All 562 tests passing across 12 test files.
Break the @alkdev/taskgraph architecture specs into dependency-ordered
implementation tasks across 8 component directories: setup, schema,
error, graph, analysis, cost-benefit, frontmatter, api, and review.
Each task has clear acceptance criteria referencing specific architecture
docs. Three review tasks serve as quality gates at critical junction
points (schemas-and-errors, graph-complete, complete-library). The
dependency graph is validated acyclic with 9 topological levels enabling
significant parallelism across independent work streams.
