Merge pull request 'fix: improve chart tooltip visibility over legend labels (#19)' (#21) from fix/simpl-resultat-19-tooltip-transparency into main

Tooltip was blending with the legend labels at the bottom of the chart,
especially when showing all categories at once. Added shadow and z-index
to ensure the tooltip stands out from the background.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/components/reports/CategoryBarChart.tsx

@@ -107,7 +107,9 @@ export default function CategoryBarChart({
                 border: "1px solid var(--border)",
                 borderRadius: "8px",
                 color: "var(--foreground)",
+                boxShadow: "0 4px 12px rgba(0,0,0,0.15)",
               }}
+              wrapperStyle={{ zIndex: 50 }}
               labelStyle={{ color: "var(--foreground)" }}
               itemStyle={{ color: "var(--foreground)" }}
             />

src/components/reports/CategoryOverTimeChart.tsx

@@ -123,7 +123,9 @@ export default function CategoryOverTimeChart({
                 border: "1px solid var(--border)",
                 borderRadius: "8px",
                 color: "var(--foreground)",
+                boxShadow: "0 4px 12px rgba(0,0,0,0.15)",
               }}
+              wrapperStyle={{ zIndex: 50 }}
               labelStyle={{ color: "var(--foreground)" }}
               itemStyle={{ color: "var(--foreground)" }}
               filterNull