Realistic-upload showcase (PLAN §247), first slice. A stage-1 front-end reads
dropped files and materializes them into an OKF bundle {concept_path: text} +
provenance; receive() wires extract -> import_bundle -> verdict. This slice
covers .txt/.md (stdlib only); .zip/.csv/folder/.docx/.pptx follow.
- Front-end lives in tests/ (showcase/dev-scoped), core stays stdlib-only:
dependencies=[] untouched; python-docx/python-pptx added to the [dev] extra
(used from stage 2d/2e), never a public [extract] extra (not v1 per PLAN).
- .txt injection -> guard T1 -> REJECT; clean .txt -> ADMIT; a dropped .md keeps
its frontmatter so a dangerous value -> T2 REJECT; an index.* upload
materializes onto the reserved uploads/index.md -> T4 REJECT.
- Detach-proof: neuter extraction to an empty bundle -> the poisoned upload
ADMITs, proving the verdict depends on extraction carrying the payload.
Tests 282 -> 288.
