refactor(admin): use inline pixel heights for overview charts

Refactors the admin overview dashboard charts to use inline pixel heights (up to 150px) instead of CSS variables and percentage-based heights. This provides more robust rendering and layout control.

Changes include:
- Replacing `Height` with `HeightPx` in chart bar structures.
- Rendering inline styles for height and width on charts and status bars.
- Adding fallback data attributes (`data-height-px`, `data-chart-value`, etc.) and loading a new fallback script (`25-admin-charts.js`).
- Updating and expanding test coverage to assert correct scaling and HTML rendering.

backend/libs/handlers/accounts_test.go

@@ -707,24 +707,60 @@ func TestAdminOverviewChartsUseZeroAndFullHeights(t *testing.T) {
 	for i, bar := range overview.UploadDays {
 		want := 0
 		if i == len(overview.UploadDays)-1 {
-			want = 100
+			want = 150
 		}
-		if bar.Height != want {
-			t.Fatalf("upload bar %d height = %d, want %d", i, bar.Height, want)
+		if bar.HeightPx != want {
+			t.Fatalf("upload bar %d height = %d, want %d", i, bar.HeightPx, want)
 		}
 	}
 	for i, bar := range overview.StorageDays {
 		want := 0
 		if i == len(overview.StorageDays)-1 {
-			want = 100
+			want = 150
 		}
-		if bar.Height != want {
-			t.Fatalf("storage bar %d height = %d, want %d", i, bar.Height, want)
+		if bar.HeightPx != want {
+			t.Fatalf("storage bar %d height = %d, want %d", i, bar.HeightPx, want)
 		}
 	}
+	if overview.StatusBars[0].WidthPercent != 100 {
+		t.Fatalf("active status width = %d, want 100", overview.StatusBars[0].WidthPercent)
+	}
 }
 
-func TestAdminOverviewRendersBarHeightVariables(t *testing.T) {
+func TestAdminOverviewChartsScaleRelativeToVisibleRange(t *testing.T) {
+	now := time.Now().UTC()
+	today := time.Date(now.Year(), now.Month(), now.Day(), 12, 0, 0, 0, time.UTC)
+	yesterday := today.AddDate(0, 0, -1)
+	twoDaysAgo := today.AddDate(0, 0, -2)
+	boxes := []services.AdminBox{
+		{ID: "today-1", CreatedAt: today, TotalSize: 30},
+		{ID: "today-2", CreatedAt: today, TotalSize: 30},
+		{ID: "today-3", CreatedAt: today, TotalSize: 30},
+		{ID: "yesterday-1", CreatedAt: yesterday, TotalSize: 20},
+		{ID: "yesterday-2", CreatedAt: yesterday, TotalSize: 20},
+		{ID: "two-days-ago", CreatedAt: twoDaysAgo, TotalSize: 10},
+	}
+	overview := buildAdminOverview(boxes, services.AdminStats{TotalBoxes: 6, ExpiredBoxes: 2, ProtectedBoxes: 1})
+
+	last := len(overview.UploadDays) - 1
+	if overview.UploadDays[last].HeightPx != 150 {
+		t.Fatalf("3-upload day height = %d, want 150", overview.UploadDays[last].HeightPx)
+	}
+	if overview.UploadDays[last-1].HeightPx != 100 {
+		t.Fatalf("2-upload day height = %d, want 100", overview.UploadDays[last-1].HeightPx)
+	}
+	if overview.UploadDays[last-2].HeightPx != 50 {
+		t.Fatalf("1-upload day height = %d, want 50", overview.UploadDays[last-2].HeightPx)
+	}
+	if overview.StorageDays[last].HeightPx != 150 || overview.StorageDays[last-1].HeightPx != 66 || overview.StorageDays[last-2].HeightPx != 16 {
+		t.Fatalf("storage heights = %d/%d/%d, want 150/66/16", overview.StorageDays[last].HeightPx, overview.StorageDays[last-1].HeightPx, overview.StorageDays[last-2].HeightPx)
+	}
+	if overview.StatusBars[0].WidthPercent != 100 || overview.StatusBars[1].WidthPercent != 50 || overview.StatusBars[2].WidthPercent != 25 {
+		t.Fatalf("status widths = %d/%d/%d, want 100/50/25", overview.StatusBars[0].WidthPercent, overview.StatusBars[1].WidthPercent, overview.StatusBars[2].WidthPercent)
+	}
+}
+
+func TestAdminOverviewRendersInlineBarDimensions(t *testing.T) {
 	app, cleanup := newTestApp(t)
 	defer cleanup()
 	adminToken := createAdminSession(t, app)
@@ -738,11 +774,26 @@ func TestAdminOverviewRendersBarHeightVariables(t *testing.T) {
 		t.Fatalf("AdminDashboard status = %d, body = %s", response.Code, response.Body.String())
 	}
 	body := response.Body.String()
-	if !strings.Contains(body, "--bar-height: 100%") {
-		t.Fatalf("admin overview did not render a full-height bar: %s", body)
+	if !strings.Contains(body, `style="height: 150px"`) {
+		t.Fatalf("admin overview did not render a full-height pixel bar: %s", body)
 	}
-	if strings.Contains(body, `style="height:`) {
-		t.Fatalf("admin overview still uses fragile percent height styles: %s", body)
+	if !strings.Contains(body, `data-height-px="150"`) || !strings.Contains(body, `data-chart-value=`) {
+		t.Fatalf("admin overview did not render chart fallback data attributes: %s", body)
+	}
+	if !strings.Contains(body, `style="height: 0px"`) {
+		t.Fatalf("admin overview did not render zero pixel bars: %s", body)
+	}
+	if !strings.Contains(body, `style="width: 100%"`) {
+		t.Fatalf("admin overview did not render a full-width status bar: %s", body)
+	}
+	if !strings.Contains(body, `data-width-percent="100"`) || !strings.Contains(body, `data-stat-value=`) {
+		t.Fatalf("admin overview did not render status fallback data attributes: %s", body)
+	}
+	if strings.Contains(body, "--bar-height") {
+		t.Fatalf("admin overview still uses css variable bar heights: %s", body)
+	}
+	if !strings.Contains(body, "/static/js/25-admin-charts.js?version=test") {
+		t.Fatalf("admin overview did not load chart fallback script: %s", body)
 	}
 }