acquire-sources

## Boundary: literature-review → acquire-sources → ingest-source `literature-review` runs SEARCH — it builds the graded guide and BibTeX. **It downloads nothing.** `acquire-sources` runs ACQUISITION — it turns the A+B graded guide into PDF files on disk, and for everything it cannot fetch automatically it writes a **manual-download worklist** (`acquisition-todo.md`). **This skill owns all downloading.** `ingest-source` runs INTAKE — it reads an already-acquired original. It does **not** download, and it **hard-stops** rather than silently substituting a preprint/review for a missing original. Sequence: literature-review once → **acquire-sources once (re-run to reconcile)** → ingest-source N times. # Acquire Sources (OA auto-download + manual worklist) Get the actual PDFs onto disk before ingest. Two outcomes per source: either an Open-Access copy is fetched automatically into the shared library (`<library>/pdf/`), or the source goes onto a worklist the user clears manually (university VPN / library proxy reach far more originals than a bot can — publishers block automated downloads). The manual worklist is a **first-class output, not a failure**: it is the bridge that lets the human do what the agent cannot. **Announce at start:** "Using acquire-sources to obtain the A+B PDFs and build a manual-download worklist for the rest." <SOFT-GATE> Before closing acquisition, check: (1) every A+B source in `literaturguide.md` is in exactly one bucket: `downloaded` | `already-pr...