fix(web): iPhone 键盘收起后顶栏复位，积分块与盘面芯片同高

frontend/src/app/globals.css

@@ -882,7 +882,51 @@ button:disabled { cursor: default; opacity: .45; }
   content: "";
 }
 .chat-header-actions button > svg { width: 14px; height: 14px; }
-.credit-button { min-height: 44px; display: inline-flex; align-items: center; justify-content: center; gap: var(--space-2); padding: 0 var(--space-3); cursor: pointer; font-size: var(--type-caption); font-variant-numeric: tabular-nums; transition: background-color 120ms ease-out, transform 120ms ease-out; min-width: 64px; border: 1px solid var(--color-border); border-radius: var(--radius-md); background: var(--color-canvas-soft); color: var(--color-ink-secondary); font-weight: 500; }
+/* Header chips share one size. `.chat-header-actions button` is 32px and
+   more specific than `.credit-button`, which is why the credit pill looked
+   shorter than 「当前盘面」(BUG-921). */
+.chat-header-actions .credit-button,
+.chat-header-rectification .rectification-board-peek {
+  position: relative;
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  height: 40px;
+  min-height: 40px;
+  padding: 0 var(--space-3);
+  gap: var(--space-2);
+  border: 1px solid var(--color-border);
+  border-radius: var(--radius-md);
+  background: var(--color-canvas-soft);
+  color: var(--color-ink-secondary);
+  font-size: var(--type-body-sm);
+  font-weight: 500;
+  font-variant-numeric: tabular-nums;
+  cursor: pointer;
+  transition: background-color 120ms ease-out, transform 120ms ease-out;
+}
+.chat-header-actions .credit-button::before,
+.chat-header-rectification .rectification-board-peek::before {
+  position: absolute;
+  inset: -2px;
+  content: "";
+}
+.credit-button {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  gap: var(--space-2);
+  padding: 0 var(--space-3);
+  cursor: pointer;
+  font-size: var(--type-body-sm);
+  font-variant-numeric: tabular-nums;
+  transition: background-color 120ms ease-out, transform 120ms ease-out;
+  border: 1px solid var(--color-border);
+  border-radius: var(--radius-md);
+  background: var(--color-canvas-soft);
+  color: var(--color-ink-secondary);
+  font-weight: 500;
+}
 
 .conversation { min-width: 0; min-height: 0; overflow-x: hidden; overflow-y: auto; overscroll-behavior: contain; padding-bottom: var(--composer-reserve); background: var(--color-canvas); }
 /* Empty state. The greeting is bottom-aligned inside the conversation row and
@@ -1892,8 +1936,9 @@ input:not([type="radio"]):not([type="checkbox"]):not([class^="ant-"]):not([class
   [data-sidebar="sidebar"][data-mobile-open="true"] { visibility: visible; transform: translateX(0); }
   .sidebar-scrim { position: fixed; z-index: 11; inset: 0; display: block; border: 0; background: var(--color-scrim); opacity: 1; visibility: visible; }
   [data-sidebar="rail"] { display: none; }
-  .chat-panel { grid-template-rows: calc(64px + env(safe-area-inset-top)) minmax(0, 1fr) auto; }
-  .chat-panel.is-rectification { grid-template-rows: calc(64px + env(safe-area-inset-top)) minmax(0, 1fr); }
+  .chat-panel { grid-template-rows: calc(52px + env(safe-area-inset-top)) minmax(0, 1fr) auto; }
+  .chat-panel.is-rectification { grid-template-rows: calc(52px + env(safe-area-inset-top)) minmax(0, 1fr); }
+  .chat-panel:has(.starter-balance) { grid-template-rows: calc(52px + env(safe-area-inset-top)) minmax(0, 1fr) auto minmax(0, 1fr); }
   .chat-header { gap: var(--space-3); padding: max(0px, env(safe-area-inset-top)) var(--space-3) 0; }
   .conversation.is-empty {
     display: block;
@@ -2962,15 +3007,10 @@ input:not([type="radio"]):not([type="checkbox"]):not([class^="ant-"]):not([class
   display: none;
 }
 .chat-header-rectification .rectification-board-peek {
-  display: inline-flex;
-  align-items: center;
   justify-content: flex-end;
   width: auto;
   max-width: min(11.5rem, 42vw);
-  min-height: 44px;
   margin: 0;
-  padding: 0 var(--space-3);
-  gap: var(--space-2);
 }
 .chat-header-rectification .rectification-board-peek strong,
 .chat-header-rectification .rectification-board-peek span {
@@ -2979,6 +3019,8 @@ input:not([type="radio"]):not([type="checkbox"]):not([class^="ant-"]):not([class
   overflow: hidden;
   text-overflow: ellipsis;
   white-space: nowrap;
+  font-size: inherit;
+  font-variant-numeric: tabular-nums;
 }
 @media (max-width: 480px) {
   .chat-header-rectification .rectification-board-peek span {

frontend/src/app/layout.tsx

@@ -3,6 +3,7 @@ import localFont from "next/font/local";
 import Script from "next/script";
 import { Toaster } from "@/components/ui/sonner";
 import { StaleClientRecovery } from "@/components/stale-client-recovery";
+import { ViewportScrollLock } from "@/components/viewport-scroll-lock";
 import { themePreferenceBootScript } from "@/lib/theme-preference";
 
 // Vendored Inter latin variable (OFL). Do not switch back to next/font/google;
@@ -53,6 +54,7 @@ export default function RootLayout({ children }: Readonly<{ children: React.Reac
       </head>
       <body>
         <StaleClientRecovery />
+        <ViewportScrollLock />
         {children}
         <Toaster />
       </body>

frontend/src/components/viewport-scroll-lock.tsx

@@ -0,0 +1,12 @@
+"use client";
+
+import { useEffect } from "react";
+
+import { installViewportScrollLock } from "@/lib/viewport-scroll-lock";
+
+export function ViewportScrollLock() {
+  useEffect(() => {
+    return installViewportScrollLock(window as unknown as Parameters<typeof installViewportScrollLock>[0]);
+  }, []);
+  return null;
+}

frontend/src/lib/viewport-scroll-lock.ts

@@ -0,0 +1,85 @@
+/**
+ * iOS Safari scrolls `window` to keep a focused input in view. `html, body
+ * { overflow: hidden }` then blocks the user from dragging back, and reload
+ * restores that offset. Reset window scroll only after the keyboard is gone.
+ */
+
+export const KEYBOARD_OPEN_GAP_PX = 100;
+export const KEYBOARD_CLOSED_SLACK_PX = 1;
+
+export function isKeyboardOpen(visualHeight: number, innerHeight: number): boolean {
+  return visualHeight < innerHeight - KEYBOARD_OPEN_GAP_PX;
+}
+
+export function shouldResetWindowScroll(input: {
+  scrollY: number;
+  innerHeight: number;
+  visualViewportHeight: number | null;
+}): boolean {
+  if (input.scrollY <= 0) return false;
+  if (input.visualViewportHeight == null) return true;
+  if (isKeyboardOpen(input.visualViewportHeight, input.innerHeight)) return false;
+  return input.visualViewportHeight >= input.innerHeight - KEYBOARD_CLOSED_SLACK_PX;
+}
+
+type ViewportLike = {
+  height: number;
+  addEventListener: (type: "resize" | "scroll", listener: () => void) => void;
+  removeEventListener: (type: "resize" | "scroll", listener: () => void) => void;
+};
+
+export type ViewportScrollLockHost = {
+  matchMedia?: (query: string) => { matches: boolean };
+  visualViewport?: ViewportLike | null;
+  innerHeight: number;
+  scrollY: number;
+  scrollTo: (x: number, y: number) => void;
+  history: { scrollRestoration: string };
+  addEventListener: (type: string, listener: () => void) => void;
+  removeEventListener: (type: string, listener: () => void) => void;
+  document: {
+    addEventListener: (type: string, listener: () => void) => void;
+    removeEventListener: (type: string, listener: () => void) => void;
+  };
+  setTimeout?: (fn: () => void, ms: number) => unknown;
+};
+
+export function installViewportScrollLock(host: ViewportScrollLockHost): () => void {
+  const coarse = host.matchMedia?.("(pointer: coarse)").matches === true;
+  const viewport = host.visualViewport ?? null;
+  if (!coarse && !viewport) return () => undefined;
+
+  host.history.scrollRestoration = "manual";
+  host.scrollTo(0, 0);
+
+  const resetIfSettled = () => {
+    if (!shouldResetWindowScroll({
+      scrollY: host.scrollY,
+      innerHeight: host.innerHeight,
+      visualViewportHeight: viewport?.height ?? null,
+    })) return;
+    host.scrollTo(0, 0);
+  };
+
+  const onPageShow = () => {
+    host.scrollTo(0, 0);
+  };
+  const onFocusOut = () => {
+    const later = host.setTimeout ?? ((fn: () => void) => fn());
+    later(resetIfSettled, 300);
+  };
+
+  viewport?.addEventListener("resize", resetIfSettled);
+  viewport?.addEventListener("scroll", resetIfSettled);
+  host.addEventListener("pageshow", onPageShow);
+  host.addEventListener("orientationchange", resetIfSettled);
+  host.document.addEventListener("focusout", onFocusOut);
+
+  return () => {
+    viewport?.removeEventListener("resize", resetIfSettled);
+    viewport?.removeEventListener("scroll", resetIfSettled);
+    host.removeEventListener("pageshow", onPageShow);
+    host.removeEventListener("orientationchange", resetIfSettled);
+    host.document.removeEventListener("focusout", onFocusOut);
+  };
+}