Fix explain_unresolved() not excluding toleranced bearings like solve_location() does

Latent inconsistency flagged during the ocr.py refactor: solve_location()
already excludes a compass-word bearing (bearing_tolerance_deg set) from
its own bearings list before triangulating, since a toleranced bearing
names a sector, not a precise ray, and shouldn't be treated as if it
were one. explain_unresolved()'s bearings list didn't have the same
exclusion, so a toleranced-only bearing plus a distance clue could get
described as inconsistent geometry ('the bearing from X never crosses
the Ykm circle...') when the real reason nothing resolved is just that
the bearing was never usable for that math in the first place. Locked
in with a new test.

src/fenigma/solver.py

@@ -294,7 +294,15 @@ def explain_unresolved(location: Location, board: Board) -> str | None:
         return "waiting on " + ", ".join(unresolved_refs) + " to have a known position first"
 
     resolved = [(clue, pt) for clue in location.clues if (pt := _entity_point(board, clue.reference)) is not None]
-    bearings = [(c, p) for c, p in resolved if c.bearing_deg is not None and c.distance_km is None]
+    # A toleranced bearing (compass word, not a precise degree reading)
+    # is never used to triangulate in solve_location() either (see its
+    # own comment above), excluded here too so this explanation doesn't
+    # claim a toleranced-only bearing could resolve something when it
+    # never actually could.
+    bearings = [
+        (c, p) for c, p in resolved
+        if c.bearing_deg is not None and c.distance_km is None and c.bearing_tolerance_deg is None
+    ]
     distances = [(c, p) for c, p in resolved if c.distance_km is not None and c.bearing_deg is None]
 
     if bearings and distances: