web: unify Agent management and add a draggable link board

Replace Probe pages with directed Agent links, shared deployment controls and unified display data. Add node dragging, canvas pan and zoom, saved layouts, and per-direction link controls.

web/shared/ui/index.tsx

@@ -508,7 +508,7 @@ export function SourceButton({ variant = 'icon' }: { variant?: 'icon' | 'status'
   )
 }
 
-/** 下载文本文件（probe.json 只给一次）。 */
+/** 下载文本文件。 */
 export function downloadText(filename: string, text: string) {
   const url = URL.createObjectURL(new Blob([text], { type: 'application/json' }))
   const a = document.createElement('a')