Why: establish the authorized task workspace and its initial baseline.
Evidence: preserved precheck receipt in .task/feature-pptx-gate-reference-integrity.md; R0=cc40e10f3b4b6e41cb3a7aa0826e08dd3b8b7270.
Impact: task metadata only; the feature workspace starts at cc40e10f3b.
Refs: .task/feature-pptx-gate-reference-integrity.md