refactor(home): 校正面 15 个状态从 Home 下沉

Home() useState 66->52, useRef 41->39. Shell-facing fields merge into one object;
subtree state lives in useRectificationSurface. Chat props 20->7. Growth contract
rebaselined. Zero behavior/copy change.

frontend/src/hooks/use-rectification-surface.ts

@@ -1,6 +1,6 @@
 "use client";
 
-import type { Dispatch, MutableRefObject, SetStateAction } from "react";
+import { useEffect, useRef, useState, type Dispatch, type MutableRefObject, type SetStateAction } from "react";
 
 import { resolveSessionTitle } from "@/lib/agent-reply";
 import { rectificationOpenIdentity } from "@/lib/rectification-session-open";
@@ -27,7 +27,10 @@ import {
   openResponseFromPayload,
   type RectificationEntrySummary,
 } from "@/lib/rectification-entry";
-import type { PersistedRectificationTurn } from "@/components/conversational-birth-time-rectification";
+import type {
+  PersistedRectificationTurn,
+  RectificationChatPanel,
+} from "@/components/conversational-birth-time-rectification";
 import type { PublicLanguageModelCatalog } from "@/lib/public-models";
 import {
   hydrateRectificationCase,
@@ -38,6 +41,60 @@ import {
   type RectificationCaseSnapshotPayload,
 } from "@/lib/rectification-surface-state";
 
+export type RectificationShellState = {
+  sessionId: string | null;
+  caseId: string | null;
+  openingSessionId: string | null;
+  loading: boolean;
+  mutationPending: boolean;
+  entrySummary: RectificationEntrySummary | null;
+  entrySummarySettled: boolean;
+  error: string;
+  errorSessionId: string | null;
+};
+
+export const EMPTY_RECTIFICATION_SHELL: RectificationShellState = {
+  sessionId: null,
+  caseId: null,
+  openingSessionId: null,
+  loading: false,
+  mutationPending: false,
+  entrySummary: null,
+  entrySummarySettled: false,
+  error: "",
+  errorSessionId: null,
+};
+
+function fieldSetter<K extends keyof RectificationShellState>(
+  setRectification: Dispatch<SetStateAction<RectificationShellState>>,
+  key: K,
+): Dispatch<SetStateAction<RectificationShellState[K]>> {
+  return (value) => {
+    setRectification((current) => ({
+      ...current,
+      [key]: typeof value === "function"
+        ? (value as (prev: RectificationShellState[K]) => RectificationShellState[K])(current[key])
+        : value,
+    }));
+  };
+}
+
+export function createRectificationShellSetters(
+  setRectification: Dispatch<SetStateAction<RectificationShellState>>,
+) {
+  return {
+    setRectificationSessionId: fieldSetter(setRectification, "sessionId"),
+    setRectificationCaseId: fieldSetter(setRectification, "caseId"),
+    setRectificationOpeningSessionId: fieldSetter(setRectification, "openingSessionId"),
+    setRectificationLoading: fieldSetter(setRectification, "loading"),
+    setRectificationMutationPending: fieldSetter(setRectification, "mutationPending"),
+    setRectificationEntrySummary: fieldSetter(setRectification, "entrySummary"),
+    setRectificationEntrySummarySettled: fieldSetter(setRectification, "entrySummarySettled"),
+    setRectificationError: fieldSetter(setRectification, "error"),
+    setRectificationErrorSessionId: fieldSetter(setRectification, "errorSessionId"),
+  };
+}
+
 export type RectificationSurfaceParams = {
   account: Account | null;
   activeChartId: string;
@@ -47,11 +104,8 @@ export type RectificationSurfaceParams = {
   modelCatalog: PublicLanguageModelCatalog | null;
   persistSession: (session: ChatSession, mode?: "create" | "update") => Promise<void>;
   profile: Profile;
-  rectificationLoading: boolean;
-  rectificationMutationPending: boolean;
-  rectificationOpenInFlight: MutableRefObject<boolean>;
-  rectificationSessionId: string | null;
-  resumeRectificationSession: MutableRefObject<(session: ChatSession) => void>;
+  rectification: RectificationShellState;
+  setRectification: Dispatch<SetStateAction<RectificationShellState>>;
   sessionSelectionSource: MutableRefObject<"user" | "history">;
   sessions: ChatSession[];
   setActiveSessionId: Dispatch<SetStateAction<string>>;
@@ -60,18 +114,6 @@ export type RectificationSurfaceParams = {
   setDraftTheme: (theme: Theme | null) => void;
   setOnboardingStep: Dispatch<SetStateAction<OnboardingStep>>;
   setProfileNotice: Dispatch<SetStateAction<string>>;
-  setRectificationCaseId: Dispatch<SetStateAction<string | null>>;
-  setRectificationEntrySummary: Dispatch<SetStateAction<RectificationEntrySummary | null>>;
-  setRectificationError: Dispatch<SetStateAction<string>>;
-  setRectificationErrorSessionId: Dispatch<SetStateAction<string | null>>;
-  setRectificationLoading: Dispatch<SetStateAction<boolean>>;
-  setRectificationPendingQuestion: Dispatch<SetStateAction<string | null>>;
-  setRectificationReadonly: Dispatch<SetStateAction<boolean>>;
-  setRectificationSessionId: Dispatch<SetStateAction<string | null>>;
-  setRectificationShouldStartOpening: Dispatch<SetStateAction<boolean>>;
-  setRectificationSnapshot: Dispatch<SetStateAction<RectificationCaseSnapshotPayload | null>>;
-  setRectificationOpeningSessionId: Dispatch<SetStateAction<string | null>>;
-  setRectificationTurns: Dispatch<SetStateAction<PersistedRectificationTurn[]>>;
   setSessions: Dispatch<SetStateAction<ChatSession[]>>;
   uiPreview: MutableRefObject<boolean>;
   updateSession: (sessionId: string, change: (session: ChatSession) => ChatSession) => void;
@@ -90,11 +132,8 @@ export function useRectificationSurface(params: RectificationSurfaceParams) {
     modelCatalog,
     persistSession,
     profile,
-    rectificationLoading,
-    rectificationMutationPending,
-    rectificationOpenInFlight,
-    rectificationSessionId,
-    resumeRectificationSession,
+    rectification,
+    setRectification,
     sessionSelectionSource,
     sessions,
     setActiveSessionId,
@@ -103,18 +142,6 @@ export function useRectificationSurface(params: RectificationSurfaceParams) {
     setDraftTheme,
     setOnboardingStep,
     setProfileNotice,
-    setRectificationCaseId,
-    setRectificationEntrySummary,
-    setRectificationError,
-    setRectificationErrorSessionId,
-    setRectificationLoading,
-    setRectificationPendingQuestion,
-    setRectificationReadonly,
-    setRectificationSessionId,
-    setRectificationShouldStartOpening,
-    setRectificationSnapshot,
-    setRectificationOpeningSessionId,
-    setRectificationTurns,
     setSessions,
     uiPreview,
     updateSession,
@@ -123,6 +150,29 @@ export function useRectificationSurface(params: RectificationSurfaceParams) {
     rectificationSessionOpenerRef,
   } = params;
 
+  const rectificationSessionId = rectification.sessionId;
+  const rectificationCaseId = rectification.caseId;
+  const rectificationLoading = rectification.loading;
+  const rectificationMutationPending = rectification.mutationPending;
+
+  const setRectificationSessionId = fieldSetter(setRectification, "sessionId");
+  const setRectificationCaseId = fieldSetter(setRectification, "caseId");
+  const setRectificationOpeningSessionId = fieldSetter(setRectification, "openingSessionId");
+  const setRectificationLoading = fieldSetter(setRectification, "loading");
+  const setRectificationMutationPending = fieldSetter(setRectification, "mutationPending");
+  const setRectificationEntrySummary = fieldSetter(setRectification, "entrySummary");
+  const setRectificationError = fieldSetter(setRectification, "error");
+  const setRectificationErrorSessionId = fieldSetter(setRectification, "errorSessionId");
+
+  const [rectificationHeaderSlot, setRectificationHeaderSlot] = useState<HTMLElement | null>(null);
+  const [rectificationPendingQuestion, setRectificationPendingQuestion] = useState<string | null>(null);
+  const [rectificationReadonly, setRectificationReadonly] = useState(false);
+  const [rectificationShouldStartOpening, setRectificationShouldStartOpening] = useState(false);
+  const [rectificationTurns, setRectificationTurns] = useState<PersistedRectificationTurn[]>([]);
+  const [rectificationSnapshot, setRectificationSnapshot] = useState<RectificationCaseSnapshotPayload | null>(null);
+  const rectificationOpenInFlight = useRef(false);
+  const resumeRectificationSession = useRef<(session: ChatSession) => void>(() => undefined);
+
   async function refreshRectificationEntrySummary() {
     if (!account) return;
     try {
@@ -289,12 +339,6 @@ export function useRectificationSurface(params: RectificationSurfaceParams) {
     await openRectificationCase("new", null, null);
   }
 
-  resumeRectificationSession.current = (session) => {
-    sessionSelectionSource.current = "history";
-    void openRectificationSession(session.id);
-  };
-  rectificationSessionOpenerRef.current = openRectificationSession;
-
   function handleRectificationProfileIncomplete() {
     setRectificationError("profile_incomplete");
     setRectificationSessionId(null);
@@ -320,7 +364,41 @@ export function useRectificationSurface(params: RectificationSurfaceParams) {
     }));
   }
 
+  useEffect(() => {
+    resumeRectificationSession.current = (session) => {
+      sessionSelectionSource.current = "history";
+      void openRectificationSession(session.id);
+    };
+    rectificationSessionOpenerRef.current = openRectificationSession;
+  });
+
+  const rectificationPanel: RectificationChatPanel = {
+    caseId: rectificationCaseId ?? "",
+    sessionId: rectificationSessionId ?? "",
+    readonly: rectificationReadonly,
+    shouldStartOpening: rectificationShouldStartOpening,
+    initialTurns: rectificationTurns,
+    initialSnapshot: rectificationSnapshot,
+    pendingConsultationQuestion: rectificationPendingQuestion,
+    headerSlot: rectificationHeaderSlot,
+    onMessagesChange: handleRectificationMessagesChange,
+    onCompleted: () => {
+      void refreshAccount();
+      if (rectificationCaseId && rectificationSessionId) {
+        void refreshRectificationCase(rectificationCaseId, rectificationSessionId);
+      }
+    },
+    onPendingChange: setRectificationMutationPending,
+    onProfileIncomplete: handleRectificationProfileIncomplete,
+    onOpeningConsumed: () => setRectificationShouldStartOpening(false),
+    onRestart: () => void startNewRectification(),
+  };
+
   return {
+    rectificationHeaderSlot,
+    setRectificationHeaderSlot,
+    rectificationPanel,
+    resumeRectificationSession,
     refreshRectificationEntrySummary,
     refreshRectificationCase,
     openRectificationCase,