feat: add dashboard ActionBar component (refs #199)

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

frontend/src/features/dashboard/components/ActionBar.tsx

@@ -0,0 +1,38 @@
+/**
+ * @ai-summary Compact action bar for dashboard with Add Vehicle and Log Fuel buttons
+ */
+
+import React from 'react';
+import Button from '@mui/material/Button';
+import Add from '@mui/icons-material/Add';
+import LocalGasStation from '@mui/icons-material/LocalGasStation';
+
+interface ActionBarProps {
+  onAddVehicle: () => void;
+  onLogFuel: () => void;
+}
+
+export const ActionBar: React.FC<ActionBarProps> = ({ onAddVehicle, onLogFuel }) => {
+  return (
+    <div className="flex flex-row gap-2 items-center">
+      <Button
+        variant="contained"
+        size="small"
+        startIcon={<Add />}
+        onClick={onAddVehicle}
+        sx={{ minHeight: 44 }}
+      >
+        Add Vehicle
+      </Button>
+      <Button
+        variant="outlined"
+        size="small"
+        startIcon={<LocalGasStation />}
+        onClick={onLogFuel}
+        sx={{ minHeight: 44 }}
+      >
+        Log Fuel
+      </Button>
+    </div>
+  );
+};