Clear error state when creating new post or changing steps

- Reset saveError and isSaving when opening create form
- Clear error when navigating between steps

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/components/Map/MapView.jsx

@@ -1213,6 +1213,7 @@ export default function MapView({
   };
 
   const handlePrevStep = () => {
+    setSaveError("");
     setCreateStep((prev) => Math.max(0, prev - 1));
   };
 
@@ -1269,6 +1270,8 @@ export default function MapView({
     setImageUsers("");
     setUrlPreviewLoading(false);
     setUrlPreviewError("");
+    setSaveError("");
+    setIsSaving(false);
     setTitleTouched(false);
     setBodyTouched(false);
     setImageTouched(false);
@@ -2028,7 +2031,7 @@ export default function MapView({
                     }
                     return;
                   }
-                  if (createStep < 2) setCreateStep((p) => p + 1);
+                  if (createStep < 2) { setSaveError(""); setCreateStep((p) => p + 1); }
                   else handleSubmitPost();
                 }}
               >