Merge remote-tracking branch 'origin/codex/add-atomic-idempotency-reservation-method'

# Conflicts:
#	backend/routers/backlink_outreach.py
#	backend/services/backlink_outreach_models.py

backend/services/backlink_outreach_models.py

@@ -192,6 +192,8 @@ class SendOutreachResponse(BaseModel):
     policy_allowed: bool
     policy_reasons: List[str] = Field(default_factory=list)
     effective_sender_email: Optional[str] = None
+    duplicate: bool = False
+    retry_policy: Optional[str] = None
 
 
 class OutreachAttemptRecord(BaseModel):