fix: AreaEffect.total_value reads the MINVAL-clamped levels, not the raw field

Java's getTotalValue calls getLevels(), and GenericObject.getLevels
(GenericObject.java:1996-2002) floors at minVal — AOE's template states
MINVAL="1", so a document that writes LEVELS="0" (kirby-api's Inferna
fixture does) still prices a 1m radius instead of raising log(0).
Same defect class as Modifier.total_value, fixed yesterday.

1724 passed; corpus parity unchanged.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PrVDXgpDfQpzEGErZTLjEs

Author: pdbethke

kirby_cost/objects/modifiers/areaeffect.py

@@ -97,12 +97,18 @@ def total_value(self) -> float:
         lp = self.level_power
         lm = self.level_multiplier
         if lp > 0 and lm > 0:
-            n2 = int(math.ceil(math.log(float(self._levels) / float(lm)) / math.log(lp)))
+            # The MINVAL-clamped accessor, not the raw field: Java's
+            # getTotalValue reads getLevels(), and GenericObject.getLevels
+            # (GenericObject.java:1996-2002) floors at minVal — AOE's
+            # template states MINVAL="1", so a document that writes no
+            # LEVELS still prices a 1m radius instead of feeding log(0).
+            levels = self.levels
+            n2 = int(math.ceil(math.log(float(levels) / float(lm)) / math.log(lp)))
             if n2 < 1:
                 n2 = 1
             # Special case: IMAGES power at level 1 gets 0 level cost
             progenitor = self.progenitor
-            if progenitor is not None and progenitor.xmlid == "IMAGES" and self._levels == 1:
+            if progenitor is not None and progenitor.xmlid == "IMAGES" and levels == 1:
                 n2 = 0
             d += float(n2) * self._level_cost