feat(speedrun): match speedrun.com games only when sure

Loose name matches gave wrong links. Now a link needs one sure hit:
same name and within 1 year of IGDB, or one hit when no year is known.
V47 marks old matches (not corrected ones) for one re-check. Refs #8

readme.md

@@ -67,10 +67,13 @@ To Be Played is split into three repositories:
       N["next up: random of top 5 in order"] --> M
       M --> O["games + reason"]
   ```
-- **Speedrun games**: a backlog game counts as a speedrun game when speedrun.com has a game with the same name (and
-  a release year at most one year off, when IGDB knows it) with at least one verified run. The game detail returns
+- **Speedrun games**: a backlog game counts as a speedrun game when speedrun.com has a game with the same name (case,
+  punctuation, ™ and roman numerals ignored) and a release year at most one year off, when IGDB knows it, with at
+  least one verified run. An edition that finds nothing tries its IGDB parent game with the parent's year, else its
+  name without an edition suffix. Several same-name games and no year to decide: no link. The game detail returns
   the speedrun.com link as `speedrunUrl`. speedrun.com has no Steam or IGDB link and no key, so one queue works for
-  all users, with up to 3 requests per game and 1 request per second; a result is kept 30 days.
+  all users, with up to 3 requests per game and 1 request per second; a result is kept 30 days. Migration V47 asks
+  every stored match again once at boot, behind user requests; links set by an auditor are never touched.
 - **Achievements**: after every library sync a background job fetches the achievement schema of each owned game
   and the user's unlocks of each game whose playtime changed. One Steam call per second, so user requests keep half
   of the rate limit; it stops after 3 Steam errors in a row or when Steam hides the achievements. A Steam error never