fix(core): remove zero-findings halt condition from edge case hunter

The "HALT if zero findings" condition pressures the LLM to hallucinate
findings when reviewing trivial diffs with no branching logic. Since
this task runs non-interactively as a subagent, it cannot ask for
guidance either. Zero findings is a valid outcome for clean code.

src/core/tasks/review-edge-case-hunter.xml

@@ -57,7 +57,6 @@ No extra text, no explanations, no markdown wrapping.</output-format>
   </flow>
 
   <halt-conditions>
-    <condition>HALT if zero findings - this is suspicious, re-analyze or ask for guidance</condition>
     <condition>HALT if content is empty or unreadable</condition>
   </halt-conditions>