Update rubocop complexity thresholds for security fix

The CVE-2026-25765 security fix added an additional conditional check
to build_exclusive_url, increasing complexity metrics from 13 to 15.
Update the rubocop_todo.yml thresholds to reflect this acceptable
increase for security purposes.

Co-Authored-By: Claude Sonnet 4.5 (1M context) <noreply@anthropic.com>

Author: iMacTia

.rubocop_todo.yml

@@ -19,7 +19,7 @@ Metrics/ClassLength:
 # Offense count: 15
 # Configuration parameters: IgnoredMethods.
 Metrics/CyclomaticComplexity:
-  Max: 13
+  Max: 15
 
 # Offense count: 43
 # Configuration parameters: CountComments, CountAsOne, ExcludedMethods.
@@ -29,4 +29,4 @@ Metrics/MethodLength:
 # Offense count: 9
 # Configuration parameters: IgnoredMethods.
 Metrics/PerceivedComplexity:
-  Max: 14
+  Max: 15