Use lunar calendar input for birth date with solar conversion display.

Add LunarBirthPicker for bazi and combined forms, converting lunar input to solar for chart calculation.

Co-authored-by: Cursor <cursoragent@cursor.com>

components/modes/combined-form.tsx

@@ -9,6 +9,9 @@ import { ModeWorkspace } from "@/components/layout/mode-workspace";
 import Result from "@/components/result";
 import ResultAI from "@/components/result-ai";
 import BaziChartDisplay from "@/components/modes/bazi-chart";
+import LunarBirthPicker, {
+  todaySolarYmd,
+} from "@/components/shared/lunar-birth-picker";
 import DateTimePicker, {
   nowDateString,
   nowTimeString,
@@ -22,7 +25,7 @@ import type { GuaResult } from "@/lib/calc/hexagram";
 import { streamAiCompletion } from "@/lib/ai/client-stream";
 
 export default function CombinedForm() {
-  const [birthDate, setBirthDate] = useState("1990-01-01");
+  const [birthDate, setBirthDate] = useState(todaySolarYmd());
   const [birthTime, setBirthTime] = useState("12:00");
   const [unknownHour, setUnknownHour] = useState(false);
   const [gender, setGender] = useState<"male" | "female">("male");
@@ -163,12 +166,12 @@ export default function CombinedForm() {
       }
     >
       <ZenCard title="人和 · 生辰" subtitle="出生时空与地域" className="flex h-full min-h-0 flex-col">
-        <DateTimePicker
-          label="出生日期 / 时间"
-          date={birthDate}
+        <LunarBirthPicker
+          label="出生日期 / 时间（农历）"
+          solarDate={birthDate}
           time={birthTime}
           timeDisabled={unknownHour}
-          onDateChange={setBirthDate}
+          onSolarDateChange={setBirthDate}
           onTimeChange={setBirthTime}
         />
         <label className="flex items-center gap-2 text-xs text-muted-foreground">