feat(bar-app): inline spend chart bars/line toggle in the Spend header

Move the bars/line choice out of Settings and into the Spend section header's
blank space as a small inline toggle, so the user flips the chart style right
where the chart is. Persistence unchanged.

macos-bar/Sources/CCSBarApp/BarAnalyticsView.swift

@@ -22,6 +22,10 @@ struct BarAnalyticsView: View {
   /// Controls whether the spend sparkline renders as bars or a line graph.
   /// Passed in by BarMenuView so it reflects the user's persisted choice live.
   var spendChartStyle: SpendChartStyle = .bars
+  /// Inline flip for the spend chart style, surfaced as a small toggle in the
+  /// Spend header (using the otherwise-blank space) so the user switches
+  /// bars/line in place rather than digging into Settings. nil for `.breakdown`.
+  var onToggleSpendStyle: (() -> Void)? = nil
 
   private var lastActive: String? {
     BarFormatting.lastActiveLabel(
@@ -71,7 +75,23 @@ struct BarAnalyticsView: View {
   /// line, and a thin inline 30-day sparkline when there is real spend.
   private var spendStrip: some View {
     VStack(alignment: .leading, spacing: 5) {
-      SectionLabel("Spend")
+      HStack(spacing: 6) {
+        SectionLabel("Spend")
+        Spacer()
+        // Inline bars/line toggle in the header's blank space — no Settings trip.
+        if let toggle = onToggleSpendStyle, analytics.hasRecentData, !sparklineIsEmpty {
+          Button(action: toggle) {
+            Image(
+              systemName: spendChartStyle == .bars
+                ? "chart.line.uptrend.xyaxis" : "chart.bar.fill"
+            )
+            .font(.system(size: 10))
+          }
+          .buttonStyle(.borderless)
+          .foregroundStyle(.tertiary)
+          .help("Spend graph: switch to \(spendChartStyle == .bars ? "line" : "bars")")
+        }
+      }
       if analytics.hasRecentData {
         Text(spendCaption)
           .font(.caption2)

macos-bar/Sources/CCSBarApp/BarMenuView.swift

@@ -50,12 +50,17 @@ struct BarMenuView: View {
             accountsSection
 
             // (3) SPEND — demoted to a thin informational strip below the cockpit.
-            // spendChartStyle is threaded from the viewModel so a live change in
-            // Settings immediately updates the chart without a refresh.
+            // spendChartStyle is threaded from the viewModel and toggled inline
+            // from the Spend header, so a change updates the chart immediately.
             if let analytics = viewModel.analytics {
               Divider()
-              BarAnalyticsView(analytics: analytics, section: .spend,
-                               spendChartStyle: viewModel.spendChartStyle)
+              BarAnalyticsView(
+                analytics: analytics, section: .spend,
+                spendChartStyle: viewModel.spendChartStyle,
+                onToggleSpendStyle: {
+                  viewModel.spendChartStyle =
+                    viewModel.spendChartStyle == .bars ? .line : .bars
+                })
             }
 
             // (4) POOL ACCOUNTS — compact generic rows, subordinate.

macos-bar/Sources/CCSBarApp/BarPreferencesView.swift

@@ -62,13 +62,8 @@ struct BarPreferencesView: View {
         Text("Dark").tag(BarAppearance.dark)
       }
       .pickerStyle(.segmented)
-      // Changing this live-updates the spend chart in the open dropdown because
-      // viewModel.spendChartStyle is @Published and SpendChartStyleStore persists it.
-      Picker("Spend graph", selection: $viewModel.spendChartStyle) {
-        Text("Bars").tag(SpendChartStyle.bars)
-        Text("Line").tag(SpendChartStyle.line)
-      }
-      .pickerStyle(.segmented)
+      // Spend graph bars/line is toggled inline in the dropdown's Spend header,
+      // not here — kept out of Settings so the choice lives where the chart is.
     }
   }