Handle Overpass rate limit returned as 200 with error body

Overpass API sometimes returns HTTP 200 with a plain-text error body
containing "rate_limited" instead of a proper 429 status. Now checks
response body for this pattern before attempting JSON parse.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

apps/planner/app/lib/overpass.ts

@@ -118,7 +118,20 @@ export async function queryPois(
     throw new Error(`Overpass API error: ${response.status}`);
   }
 
-  const data = await response.json();
+  const text = await response.text();
+
+  // Overpass sometimes returns 200 with rate limit error in the body
+  if (text.includes("rate_limited")) {
+    throw new OverpassRateLimitError();
+  }
+
+  let data;
+  try {
+    data = JSON.parse(text);
+  } catch {
+    throw new Error("Overpass API returned invalid JSON");
+  }
+
   return parseResponse(data, categories);
 }