fix(automations): remove spurious third output on condition steps

A Condition (If/Else) step rendered three add-step connectors: Yes, No,
and a trailing linear "+". ConditionBranches already renders the Yes/No
branch StepLists (each with its own AddButton), while StepRenderer also
emitted a trailing AddButton after every step — including conditions.

Skip the trailing AddButton when step_type === "condition", since a
condition branches into Yes/No and has no linear continue path. Steps
after a condition are added inside one of its branches.

Fixes #256

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/components/automations/automation-builder.tsx

@@ -927,9 +927,14 @@ function StepRenderer({
         )}
       </div>
 
+      {/* A condition branches into Yes/No (rendered above by
+          ConditionBranches), so it has no linear "continue" path — adding
+          the trailing connector here would produce a spurious third output. */}
+      {!isCondition && (
         <AddButton
           onPick={(t) => props.addStepAt(parentScope, index + 1, t)}
         />
+      )}
     </>
   )
 }