fix(ui): keep mobile onboarding and login usable

Hide the dead composer during birth-time intake, replace internal
copy with user-facing hints, and keep short-screen login, location
search, and session history reachable on phones.

frontend/src/components/birth-time-intake.tsx

@@ -85,7 +85,7 @@ export function BirthTimeIntakeFields({ value, onPatch }: BirthTimeIntakeProps)
         <section className="birth-time-profile-result" aria-label="生时校正结果">
           <div className="birth-time-profile-result-heading">
             <span>出生时间记录</span>
-            <strong>{displayState.kind === "candidate" ? "候选时间" : displayState.kind === "accepted" ? "校正采用" : "引擎确认"}</strong>
+            <strong>{displayState.kind === "candidate" ? "候选时间" : displayState.kind === "accepted" ? "校正采用" : "已记录时间"}</strong>
           </div>
           <dl>
             <div>
@@ -101,7 +101,7 @@ export function BirthTimeIntakeFields({ value, onPatch }: BirthTimeIntakeProps)
             <p>这仍是未确认候选，不会自动成为出生分钟；{birthTimeConsultationOptionsCopy(value)}</p>
           )}
           {displayState.kind === "accepted" && (
-            <p>这是你从候选中选择的校正采用时间，并非引擎唯一确认分钟；后续排盘会使用它。</p>
+            <p>这是你从候选中选择的校正采用时间，不是外部档案确认的出生时间；后续排盘会使用它。</p>
           )}
         </section>
       )}