fix(chat): honor new-chat intent from secondary pages

Create a fresh local consultation for explicit new-chat navigation and keep reserved recovery from taking over its landing. Add regression tests and record validation gaps for remote review.

Co-Authored-By: Claude Code <noreply@anthropic.com>

frontend/src/app/(app)/page.tsx

@@ -1062,6 +1062,7 @@ export default function Home() {
         setStartGreeting(nextProfile.name.trim() ? createStartGreeting(nextProfile.name) : "");
         setOnboardingStep(missingProfileStep(nextProfile) ?? "name");
         setSessions(nextSessions);
+        if (bootstrapSelection.urlAction === "new-chat") writeSessionUrl(null, "replace");
         setActiveSessionId(landingSessionId);
         if (bootstrapSelection.clearStoredReturn) clearLoginSessionReturn();
         if (bootstrapSelection.urlAction === "replace-clear") writeSessionUrl(null, "replace");
@@ -1074,6 +1075,10 @@ export default function Home() {
         if (reservedConsultation?.status === "reserved") {
           const recoverySession = nextSessions.find((session) => session.id === reservedConsultation.sessionId);
           if (recoverySession) restoreConsultationRecovery(recoverySession, reservedConsultation.requestId, storedPending);
+          if (bootstrapSelection.urlAction === "new-chat") {
+            setActiveSessionId(landingSessionId);
+            setComposerNotice("");
+          }
         }
         if (modelCatalogResult.unavailable) {
           setComposerNotice("模型服务暂时不可用，当前无法发送问题。");

frontend/src/components/app-sidebar.tsx

@@ -19,7 +19,7 @@ import { usePathname } from "next/navigation";
 import { useEffect, useRef } from "react";
 import type { Ref } from "react";
 import { AppLink } from "@/components/app-link";
-import { persistLoginSessionReturn, sessionHref } from "@/lib/chat-session-url";
+import { newChatHref, persistLoginSessionReturn, sessionHref } from "@/lib/chat-session-url";
 import { prefetchSecondaryPage } from "@/lib/secondary-page-data";
 import {
   Sidebar,
@@ -248,7 +248,7 @@ export function AppSidebar({
                 {showExpandedContent ? <span>{creatingSession ? "正在创建" : "新建对话"}</span> : null}
               </SidebarMenuButton>
             ) : (
-              <SidebarMenuLink className="new-chat" tooltip="新对话" href="/" onClick={closeDrawer}>
+              <SidebarMenuLink className="new-chat" tooltip="新对话" href={newChatHref()} onClick={closeDrawer}>
                 <SquarePen size={18} strokeWidth={1.75} aria-hidden="true" />
                 {showExpandedContent ? <span>新建对话</span> : null}
               </SidebarMenuLink>

frontend/src/lib/chat-session-url.ts

@@ -1,4 +1,5 @@
 export const SESSION_URL_QUERY_KEY = "c";
+export const NEW_CHAT_QUERY_KEY = "new";
 export const SESSION_URL_RETURN_STORAGE_KEY = "jyotisha.session-url-return";
 export const SESSION_MISSING_NOTICE = "该对话不存在或已被删除";
 export const SESSION_LOOKUP_FAILED_NOTICE = "这条对话暂时读不到，请稍后重试。";
@@ -11,11 +12,20 @@ export type SessionUrlQuery = {
 
 export type BootstrapSessionSelection = {
   readonly sessionId: string;
-  readonly urlAction: "keep" | "replace-selected" | "replace-clear" | "none" | "lookup";
+  readonly urlAction: "keep" | "replace-selected" | "replace-clear" | "none" | "lookup" | "new-chat";
   readonly missing: boolean;
   readonly clearStoredReturn: boolean;
 };
 
+export function newChatHref(): string {
+  return "/?new=1";
+}
+
+export function parseNewChatIntent(search: string): boolean {
+  const params = new URLSearchParams(search.startsWith("?") ? search.slice(1) : search);
+  return params.has(NEW_CHAT_QUERY_KEY);
+}
+
 export function parseSessionUrlQuery(search: string): SessionUrlQuery {
   const params = new URLSearchParams(search.startsWith("?") ? search.slice(1) : search);
   if (!params.has(SESSION_URL_QUERY_KEY)) {
@@ -30,6 +40,7 @@ export function parseSessionUrlQuery(search: string): SessionUrlQuery {
 
 export function sessionHref(search: string, sessionId: string | null, pathname = "/"): string {
   const params = new URLSearchParams(search.startsWith("?") ? search.slice(1) : search);
+  params.delete(NEW_CHAT_QUERY_KEY);
   if (sessionId) params.set(SESSION_URL_QUERY_KEY, sessionId);
   else params.delete(SESSION_URL_QUERY_KEY);
   const query = params.toString();
@@ -79,6 +90,14 @@ export function resolveBootstrapSessionSelection(input: {
   readonly search: string;
   readonly storedReturnId: string | null;
 }): BootstrapSessionSelection {
+  if (parseNewChatIntent(input.search)) {
+    return {
+      sessionId: input.defaultSessionId,
+      urlAction: "new-chat",
+      missing: false,
+      clearStoredReturn: true,
+    };
+  }
   const query = parseSessionUrlQuery(input.search);
   if (query.present) {
     if (query.sessionId && input.listedIds.includes(query.sessionId)) {

frontend/src/lib/home-bootstrap.ts

@@ -18,7 +18,7 @@ export type LandingSession = Readonly<{
   messages: readonly unknown[];
 }>;
 
-export type LandingUrlAction = "keep" | "replace-selected" | "replace-clear" | "none" | "lookup";
+export type LandingUrlAction = "keep" | "replace-selected" | "replace-clear" | "none" | "lookup" | "new-chat";
 
 /**
  * A rectification Case is opened only when the address bar names that session
@@ -43,7 +43,7 @@ export function resolveStarterHomeLandingSessionId(
   selectedId: string,
   urlAction: LandingUrlAction,
 ): string {
-  if (urlAction === "keep" || urlAction === "replace-selected" || urlAction === "lookup") {
+  if (urlAction === "keep" || urlAction === "replace-selected" || urlAction === "lookup" || urlAction === "new-chat") {
     return selectedId;
   }
   const selected = sessions.find((session) => session.id === selectedId);
@@ -61,6 +61,7 @@ export function starterHomeLandingNeedsConsultation(
   landingId: string,
   urlAction: LandingUrlAction,
 ): boolean {
+  if (urlAction === "new-chat") return true;
   if (urlAction === "keep" || urlAction === "replace-selected" || urlAction === "lookup") return false;
   const landing = sessions.find((session) => session.id === landingId);
   return !landing || landing.sessionType === "birth_time_rectification";