refactor: consolidate duplicate panel headers into reusable component

Consolidates three duplicate header implementations in RightPanel into a
single reusable PanelHeader component, following DRY principles.

Changes:
- Created PanelHeader component in RightPanel.tsx with consistent props
- Refactored Actor Properties to use PanelHeader
- Refactored Relation Properties to use PanelHeader
- Refactored Graph Analysis to use PanelHeader (removed internal header)
- All panel headers now have consistent appearance and behavior
- Supports optional close button and required collapse functionality

Benefits:
- Eliminates code duplication across panel views
- Ensures consistent UX across all panel states
- Easier to maintain and update header behavior in one place
- Reduces bundle size by removing redundant JSX

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

src/components/Common/GraphMetrics.tsx

@@ -1,6 +1,5 @@
 import { useMemo } from 'react';
-import { IconButton, Tooltip } from '@mui/material';
-import ChevronRightIcon from '@mui/icons-material/ChevronRight';
+import { Tooltip } from '@mui/material';
 import WarningIcon from '@mui/icons-material/Warning';
 import InfoIcon from '@mui/icons-material/Info';
 import BarChartIcon from '@mui/icons-material/BarChart';
@@ -11,7 +10,6 @@ interface GraphMetricsProps {
   nodes: Actor[];
   edges: Relation[];
   onActorClick?: (actorId: string) => void;
-  onCollapse?: () => void;
 }
 
 /**
@@ -20,7 +18,7 @@ interface GraphMetricsProps {
  * Shows when no node or edge is selected in the right panel.
  * Provides insights into graph structure, connectivity, and key actors.
  */
-const GraphMetrics = ({ nodes, edges, onActorClick, onCollapse }: GraphMetricsProps) => {
+const GraphMetrics = ({ nodes, edges, onActorClick }: GraphMetricsProps) => {
   // Calculate all metrics (memoized for performance - auto-updates when nodes/edges change)
   const metrics = useMemo(() => {
     return calculateGraphMetrics(nodes, edges);
@@ -36,21 +34,6 @@ const GraphMetrics = ({ nodes, edges, onActorClick, onCollapse }: GraphMetricsPr
 
   return (
     <div className="h-full flex flex-col">
-      {/* Header */}
-      <div className="flex items-center justify-between px-3 py-2 border-b border-gray-200 bg-gray-50">
-        <div className="flex items-center space-x-2">
-          <BarChartIcon className="text-blue-600" fontSize="small" />
-          <h2 className="text-sm font-semibold text-gray-700">Graph Analysis</h2>
-        </div>
-        {onCollapse && (
-          <Tooltip title="Collapse Panel (Ctrl+I)">
-            <IconButton size="small" onClick={onCollapse}>
-              <ChevronRightIcon fontSize="small" />
-            </IconButton>
-          </Tooltip>
-        )}
-      </div>
-
       {/* Scrollable Content */}
       <div className="flex-1 overflow-y-auto overflow-x-hidden px-3 py-3 space-y-4">
         {/* Overview Section */}

src/components/Panels/RightPanel.tsx

@@ -27,6 +27,35 @@ interface Props {
   onClose: () => void;
 }
 
+/**
+ * PanelHeader - Reusable header component for right panel views
+ */
+interface PanelHeaderProps {
+  title: string;
+  onClose?: () => void;
+  onCollapse: () => void;
+}
+
+const PanelHeader = ({ title, onClose, onCollapse }: PanelHeaderProps) => (
+  <div className="flex items-center justify-between px-3 py-2 border-b border-gray-200 bg-gray-50">
+    <h2 className="text-sm font-semibold text-gray-700">{title}</h2>
+    <div className="flex items-center space-x-1">
+      {onClose && (
+        <Tooltip title="Close (Esc)">
+          <IconButton size="small" onClick={onClose}>
+            ✕
+          </IconButton>
+        </Tooltip>
+      )}
+      <Tooltip title="Collapse Panel (Ctrl+I)">
+        <IconButton size="small" onClick={onCollapse}>
+          <ChevronRightIcon fontSize="small" />
+        </IconButton>
+      </Tooltip>
+    </div>
+  </div>
+);
+
 const RightPanel = ({ selectedNode, selectedEdge, onClose }: Props) => {
 
   const {
@@ -181,7 +210,8 @@ const RightPanel = ({ selectedNode, selectedEdge, onClose }: Props) => {
         className="h-full bg-white border-l border-gray-200 flex flex-col"
         style={{ width: `${rightPanelWidth}px` }}
       >
-        <GraphMetrics nodes={nodes} edges={edges} onCollapse={collapseRightPanel} />
+        <PanelHeader title="Graph Analysis" onCollapse={collapseRightPanel} />
+        <GraphMetrics nodes={nodes} edges={edges} />
         {ConfirmDialogComponent}
       </div>
     );
@@ -196,22 +226,7 @@ const RightPanel = ({ selectedNode, selectedEdge, onClose }: Props) => {
         className="h-full bg-white border-l border-gray-200 flex flex-col"
         style={{ width: `${rightPanelWidth}px` }}
       >
-        {/* Header */}
-        <div className="flex items-center justify-between px-3 py-2 border-b border-gray-200 bg-gray-50">
-          <h2 className="text-sm font-semibold text-gray-700">Actor Properties</h2>
-          <div className="flex items-center space-x-1">
-            <Tooltip title="Close (Esc)">
-              <IconButton size="small" onClick={onClose}>
-                ✕
-              </IconButton>
-            </Tooltip>
-            <Tooltip title="Collapse Panel (Ctrl+I)">
-              <IconButton size="small" onClick={collapseRightPanel}>
-                <ChevronRightIcon fontSize="small" />
-              </IconButton>
-            </Tooltip>
-          </div>
-        </div>
+        <PanelHeader title="Actor Properties" onClose={onClose} onCollapse={collapseRightPanel} />
 
         {/* Scrollable content */}
         <div className="flex-1 overflow-y-auto overflow-x-hidden px-3 py-3 space-y-4">
@@ -377,22 +392,7 @@ const RightPanel = ({ selectedNode, selectedEdge, onClose }: Props) => {
         className="h-full bg-white border-l border-gray-200 flex flex-col"
         style={{ width: `${rightPanelWidth}px` }}
       >
-        {/* Header */}
-        <div className="flex items-center justify-between px-3 py-2 border-b border-gray-200 bg-gray-50">
-          <h2 className="text-sm font-semibold text-gray-700">Relation Properties</h2>
-          <div className="flex items-center space-x-1">
-            <Tooltip title="Close (Esc)">
-              <IconButton size="small" onClick={onClose}>
-                ✕
-              </IconButton>
-            </Tooltip>
-            <Tooltip title="Collapse Panel (Ctrl+I)">
-              <IconButton size="small" onClick={collapseRightPanel}>
-                <ChevronRightIcon fontSize="small" />
-              </IconButton>
-            </Tooltip>
-          </div>
-        </div>
+        <PanelHeader title="Relation Properties" onClose={onClose} onCollapse={collapseRightPanel} />
 
         {/* Scrollable content */}
         <div className="flex-1 overflow-y-auto overflow-x-hidden px-3 py-3 space-y-4">