fix(sports_rankings): skip a malformed poll entry; rank each side by its own id (#791)

* fix(sports_rankings): skip a malformed poll entry; rank each side by its own id

The two review points deferred on #789 until sports_rankings was the only
copy (the nine scoreboards adopted it in ledmatrix-plugins #648):

- A poll entry whose "current" is None or a string raised TypeError at
  `current_rank <= 0`; the broad except returned {} without setting the
  cache timestamp, so every team lost its rank and the standings were
  re-fetched on every update. The entry is now skipped.
- _ranked_positions() fell back to abbreviations for BOTH sides when only
  one side's id was unparseable, so a colliding abbreviation could rank the
  wrong school. It now decides id-or-abbreviation per side.

Well-formed ESPN data (ids on both sides, int ranks) ranks as before.
SPORTS_UNIFICATION.md: family 8 marked done and adopted.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* docs(changelog): a numeric-string rank is still accepted; say which values are skipped

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

CHANGELOG.md

@@ -19,6 +19,17 @@ accepts both, but the store flags the old spelling as deprecated
 
 ## Unreleased
 
+### Fixes
+
+- `SportsRankingsMixin` (#789's deferred review points, now that it is the
+  only copy): a poll entry whose `current` cannot be converted to an
+  integer (`None`, a non-numeric string) is skipped instead of throwing
+  away the whole poll -- which left
+  every team unranked and re-fetched the standings on every update -- and
+  `_ranked_positions()` decides id-or-abbreviation per side, so one side
+  without an id no longer drops the other side's id and lets a shared
+  abbreviation rank the wrong school. Well-formed ESPN data ranks as before.
+
 ## 3.8.5
 
 Fewer ESPN requests on the hourly schedule refresh (#754), and sports