feat: add Ctrl+F search bar to canvas

- Ctrl+F / Cmd+F opens floating search bar at top-center of canvas
- Filters nodes by label, IP, hostname and service name (case-insensitive)
- Shows match count and no-results message
- Click result selects node and flies camera to it with animation
- Escape or × closes the bar
- groupRect nodes excluded from results
- Handles grouped nodes with correct absolute position for navigation

frontend/src/components/canvas/CanvasContainer.tsx

@@ -18,6 +18,7 @@ import { useThemeStore } from '@/stores/themeStore'
 import { THEMES } from '@/utils/themes'
 import { nodeTypes } from './nodes/nodeTypes'
 import { edgeTypes } from './edges/edgeTypes'
+import { SearchBar } from './SearchBar'
 import type { NodeData, EdgeData } from '@/types'
 
 interface CanvasContainerProps {
@@ -88,6 +89,7 @@ export function CanvasContainer({ onConnect: onConnectProp, onEdgeDoubleClick, o
           size={1}
           color={theme.colors.canvasDotColor}
         />
+        <SearchBar />
         <Controls>
           <ControlButton
             onClick={() => setLassoMode((m) => !m)}