second-brain-ingest

Process raw sources in a Second Brain vault (`raw/` folder — articles, papers, notes, transcripts clipped via Obsidian Web Clipper) into structured `wiki/` pages — one summary per source under `wiki/sources/`, plus extracted `entities/`, `concepts/`, and `synthesis/` notes with bidirectional `[[wikilinks]]` and an updated `wiki/index.md` and `log.md`.