Rows resolving to the same (bgg_id, version_id — or both version-
unknown) are the same physical game read twice unless their extraction
cues conflict (two editions stay separate). The survivor is the read
whose transcription matches the BGG name; losers are marked
match_status=merged with a new merged_into column — no row is ever
deleted, and older matches.csv files without the column still read.
Downstream: diff skips merged rows but folds their photos into the
survivor's to_add provenance; enrich and the review passes ignore them.
The web UI gains a Merges section ("Jokin Ha... merged into Joking
Hazard") with a veto (v key) that restores the row as a distinct
approved match, plus a merged catalog chip and header tally.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
compute_diff is a pure function over matches + collection items: new
games land in to_add.csv (carrying a confident version when matching
produced one); owned version-less entries with version_auto/approved
matches produce additive to_update.csv rows keyed by collid, consuming
distinct collids when photos show two editions; entries that already
carry a version are never touched — disagreements are reported in the
summary. Unseen collection entries are listed informationally. Live API
mode activates when BGG_API_TOKEN + username exist; otherwise the two
hand-pulled snapshot XMLs (real 2018 collection, 79 unique copies after
collid dedupe) are used, and they double as parsing fixtures in tests.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>