feat(web): W4-F rebuild agent conversation and drawer with agentui components

- Port agentui (MIT, ashish200729/agentui@b2b752b) Message/MessageBubble/MessageScroller,
  StreamingResponse, ToolResult/ToolApproval, TodoList, ApprovalCard, CodeBlock/FileDiff,
  Citations, PromptInput into components/agentui; drop motion/shiki/Next, switch colors,
  type scale, radii, durations and easing to semantic tokens, honour reduced motion
- Conversation: streaming cursor, collapsible thinking, tool cards with kind/scope/risk/
  idempotency badges and audit idempotency key, prominent server-rejection state for both
  whitelist rejections and unauthorized errors, compaction markers, budget meters with
  over-limit state, approval cards (admin session only), two-column final report
  (model said vs system verified with task/record links), follow-scroll with jump-to-bottom
- Composer: Enter send / Shift+Enter newline, stop = abort (confirmed), append,
  execute/plan_only switch, "execute this plan" from finished plan_only runs
- Session list sidebar with status filter and usage; reconnect/error banners with retry
- Drawer: route-derived context (entity/site/task), minimize to a live mini dock
- Fix stream refetch race when the run switches from loading to finished

Co-Authored-By: Claude Opus 5.5 <[email protected]>

apps/web/app/components/agentui/file-diff.tsx

@@ -0,0 +1,99 @@
+// Adapted from agentui (https://github.com/ashish200729/agentui), components/agents/file-diff.tsx
+// Copyright (c) 2026 Saurabh Chauhan. MIT License, see ./LICENSE-agentui.md
+// 改造:新增/删除行底色 emerald/rose → success/destructive 洗层(并保留 +/− 符号,不只靠颜色);不做语法高亮(去 shiki);
+// 折叠用 Disclosure;maxHeight 改 Tailwind 类;用于展示路径类变更(如整理记录的入库目标)。
+import { ChevronDown, FileCode2 } from "lucide-react";
+import { type ReactNode, useId, useState } from "react";
+import { cn } from "~/lib/utils.ts";
+import { CHEVRON_CLASS, Disclosure } from "./disclosure.tsx";
+
+export type FileDiffLineType = "added" | "removed" | "context";
+
+export interface FileDiffLine {
+  id: string;
+  type?: FileDiffLineType;
+  content: ReactNode;
+  /** 行尾附注(如状态) */
+  note?: ReactNode;
+}
+
+function Count({ value, type }: { value: number; type: "added" | "removed" }) {
+  if (!value) return null;
+  return (
+    <span className={cn("font-mono text-meta tabular-nums", type === "added" ? "text-success" : "text-destructive")}>
+      {type === "added" ? "+" : "−"}
+      {value}
+    </span>
+  );
+}
+
+export function FileDiff({
+  file,
+  lines,
+  defaultOpen = true,
+  maxHeightClassName = "max-h-56",
+  className,
+}: {
+  file: ReactNode;
+  lines: FileDiffLine[];
+  defaultOpen?: boolean;
+  maxHeightClassName?: string;
+  className?: string;
+}) {
+  const id = useId();
+  const [open, setOpen] = useState(defaultOpen);
+  const added = lines.filter((l) => l.type === "added").length;
+  const removed = lines.filter((l) => l.type === "removed").length;
+  return (
+    <div className={cn("w-full min-w-0 overflow-hidden rounded-lg border border-border/60 text-sm", className)}>
+      <button
+        type="button"
+        aria-expanded={open}
+        aria-controls={id}
+        onClick={() => setOpen(!open)}
+        className="flex h-8 w-full cursor-pointer items-center gap-2 px-2.5 text-left outline-none transition-colors duration-micro hover:bg-foreground/[0.03] focus-visible:ring-2 focus-visible:ring-ring"
+      >
+        <FileCode2 aria-hidden className="size-3.5 shrink-0 text-muted-foreground/70" />
+        <span className="min-w-0 flex-1 truncate text-meta text-foreground/85">{file}</span>
+        <Count value={added} type="added" />
+        <Count value={removed} type="removed" />
+        <ChevronDown aria-hidden className={cn("size-3.5", CHEVRON_CLASS, open && "rotate-180")} />
+      </button>
+      <Disclosure id={id} open={open}>
+        <div className={cn("overflow-auto border-t border-border/50 py-1", maxHeightClassName)}>
+          <ul className="font-mono text-meta leading-5">
+            {lines.map((l) => (
+              <li
+                key={l.id}
+                className={cn(
+                  "grid grid-cols-[1.25rem_minmax(0,1fr)_auto] gap-1 pr-2.5",
+                  l.type === "added" && "bg-success/[0.08]",
+                  l.type === "removed" && "bg-destructive/[0.08]",
+                )}
+              >
+                <span
+                  aria-hidden
+                  className={cn(
+                    "text-center select-none",
+                    l.type === "added"
+                      ? "text-success"
+                      : l.type === "removed"
+                        ? "text-destructive"
+                        : "text-muted-foreground/50",
+                  )}
+                >
+                  {l.type === "added" ? "+" : l.type === "removed" ? "−" : " "}
+                </span>
+                <span className="min-w-0 break-all text-foreground/85">
+                  <span className="sr-only">{l.type === "added" ? "新增:" : l.type === "removed" ? "移除:" : ""}</span>
+                  {l.content}
+                </span>
+                {l.note ? <span className="shrink-0 font-sans text-muted-foreground">{l.note}</span> : null}
+              </li>
+            ))}
+          </ul>
+        </div>
+      </Disclosure>
+    </div>
+  );
+}