Directory-scan ingestion deduped only by content hash, so when a file at a known path changed, the new hash missed the existing raw and a second row was inserted for the same source_path — both rows then generated wiki pages, accumulating duplicates. Make source path the primary dedup key: same path + same hash skips, same path + changed hash updates the existing raw in place (reset to pending, re-process), falling back to the content-hash check only for genuine copies at new paths. Reprocessing reuses the same rawId, so deleteExclusiveBySourceRawId cleans the old pages before regeneration — no duplicate rows and no duplicate pages. findBySourcePath gains LIMIT 1 to tolerate pre-existing duplicates; docs/fix-duplicate-raws.sql remediates existing data.
Closes#271
