feat(frontend): refine app shell and assistant editors

frontend/src/components/workflow/WorkflowCanvas.tsx

@@ -8,6 +8,7 @@ import {
   Controls,
   type Edge,
   MarkerType,
+  MiniMap,
   type Node,
   type NodeChange,
   type OnConnectEnd,
@@ -561,7 +562,7 @@ export function WorkflowCanvas({
       <NodeActionContext.Provider value={nodeActions}>
         <EdgeActionContext.Provider value={edgeActions}>
           <div className="relative h-full w-full min-h-[560px]">
-            <section className="relative h-full w-full overflow-hidden rounded-2xl border border-hairline bg-canvas-soft shadow-sm">
+            <section className="relative h-full w-full overflow-hidden bg-canvas-soft">
               <div
                 aria-hidden
                 className="pointer-events-none absolute -right-24 -top-24 z-0 h-80 w-80 rounded-full opacity-30 blur-3xl"
@@ -616,6 +617,17 @@ export function WorkflowCanvas({
                 <Controls
                   className="!rounded-xl !border !border-hairline !bg-card !shadow-sm [&_button]:!border-hairline [&_button]:!bg-card [&_button]:!text-foreground"
                 />
+                <MiniMap
+                  position="bottom-left"
+                  pannable
+                  zoomable
+                  nodeBorderRadius={8}
+                  nodeColor="var(--surface-strong)"
+                  nodeStrokeColor="var(--hairline-strong)"
+                  maskColor="color-mix(in srgb, var(--background) 68%, transparent)"
+                  className="!rounded-xl !border !border-hairline !bg-card/90 !shadow-sm"
+                  style={{ left: 56, width: 176, height: 108 }}
+                />
                 <Panel position="top-left">
                   <TooltipProvider>
                     <div className="flex flex-col gap-2">

frontend/src/components/workflow/WorkflowEditor.tsx

@@ -23,7 +23,7 @@ export function WorkflowEditor(props: WorkflowEditorProps) {
 
   if (loading) {
     return (
-      <div className="flex h-full w-full items-center justify-center rounded-2xl border border-hairline bg-canvas-soft text-muted-foreground">
+      <div className="flex h-full w-full items-center justify-center bg-canvas-soft text-muted-foreground">
         <Loader2 className="mr-2 animate-spin" size={18} />
         正在加载节点目录…
       </div>
@@ -31,7 +31,7 @@ export function WorkflowEditor(props: WorkflowEditorProps) {
   }
   if (error) {
     return (
-      <div className="flex h-full w-full items-center justify-center rounded-2xl border border-hairline bg-canvas-soft px-6 text-center text-sm text-destructive">
+      <div className="flex h-full w-full items-center justify-center bg-canvas-soft px-6 text-center text-sm text-destructive">
         加载节点目录失败:{error}
       </div>
     );