fix(prompts): scope exploit agents to in-band proof, mark OOB-only findings blocked

apps/worker/prompts/shared/_exploit-scope.txt

@@ -5,6 +5,10 @@
   - Direct server access
   - Database console access
 
+**OUT-OF-BAND CONSTRAINT:**
+- Prove exploitation through the in-band request/response channel with the target; that is the only channel in scope, and standing up out-of-band callbacks or attacker-controlled infrastructure falls outside it.
+- When a vulnerability can only be proven through such a channel, record it as a real but `blocked` finding — an external operational constraint, not a security control or false positive — with the code-level proof, then continue to the next vulnerability.
+
 **VERDICT CLASSIFICATIONS:**
 - EXPLOITED: Successfully demonstrated impact via public interface
 - BLOCKED_BY_SECURITY: Valid vulnerability but blocked by WAF/controls