Tighten downloads chart y-axis to "current + 1k"

`nice_upper_bound` rounded the y-axis cap to 20k for a 10.3k cumulative
total, squashing the trend line into the lower third of the card. Cap
the axis at `max(current_cumulative + 1000, 1000)` instead so the
latest point lands near the top of the chart area and the rise is
visually obvious.

Co-authored-by: Open Codex <hff582580@gmail.com>

Author: LEON-gittech

.github/npm-total-downloads.svg

@@ -202,7 +202,10 @@ def generate_svg(package_name, cumulative_rows):
     chart_h = chart_bottom - chart_top
 
     max_downloads = max([downloads for _, downloads in cumulative_rows] or [0])
-    upper = nice_upper_bound(max_downloads)
+    # Cap the y-axis at "current cumulative + 1k" so the latest point sits
+    # near the top of the trend area instead of getting squashed when
+    # `nice_upper_bound` jumps to the next 2× / 5× / 10× tier.
+    upper = max(max_downloads + 1000, 1000)
 
     def x_for(index):
         if len(cumulative_rows) <= 1: