fix(web): fix remaining request reference in plot endpoint

src/disk_checker/web/routes.py

@@ -111,13 +111,13 @@ async def generate_plot_endpoint(
 
         # Determine metrics
         available = sorted(df["metric"].unique())
-        if request.metric:
-            if request.metric not in available:
+        if metric:
+            if metric not in available:
                 raise HTTPException(
                     status_code=400,
-                    detail=f"Metric {request.metric} not found"
+                    detail=f"Metric {metric} not found"
                 )
-            metrics = [request.metric]
+            metrics = [metric]
         else:
             totals = df.groupby("metric")["count"].sum().sort_values(ascending=False)
             metrics = [totals.index[0]]