Replace RSC streaming with /api/ai Route Handler for Docker reliability.

Server Actions + createStreamableValue kept failing in production; fetch-based text stream avoids RSC serialization issues and shows readable error messages.

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

components/modes/combined-form.tsx

@@ -1,7 +1,6 @@
 "use client";
 
 import { useState } from "react";
-import { readStreamableValue } from "ai/rsc";
 import { Compass } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { Textarea } from "@/components/ui/textarea";
@@ -18,8 +17,7 @@ import RegionSelect, {
 } from "@/components/shared/region-select";
 import { calculateBazi, type BaziChart } from "@/lib/calc/bazi";
 import type { GuaResult } from "@/lib/calc/hexagram";
-import { getCombinedAnswer } from "@/app/actions/combined";
-import { ERROR_PREFIX } from "@/lib/constant";
+import { streamAiCompletion } from "@/lib/ai/client-stream";
 
 export default function CombinedForm() {
   const [birthDate, setBirthDate] = useState("1990-01-01");
@@ -109,39 +107,35 @@ export default function CombinedForm() {
     setShowAi(true);
 
     try {
-      const stream = await getCombinedAnswer({
-        birth: {
-          date: birthDate,
-          time: unknownHour ? "12:00" : birthTime,
-          gender,
-          longitude: birthLocation!.longitude,
-          unknownHour,
+      await streamAiCompletion(
+        {
+          mode: "combined",
+          payload: {
+            birth: {
+              date: birthDate,
+              time: unknownHour ? "12:00" : birthTime,
+              gender,
+              longitude: birthLocation!.longitude,
+              unknownHour,
+            },
+            birthPlaceName: birthLocation!.name,
+            currentPlaceName: currentLocation!.name,
+            currentLongitude: currentLocation!.longitude,
+            calcDate,
+            calcTime,
+            question,
+            hexagram: withHexagram && guaData
+              ? {
+                  guaMark: guaData.result.guaMark,
+                  guaTitle: guaData.result.guaTitle,
+                  guaResult: guaData.result.guaResult,
+                  guaChange: guaData.result.guaChange,
+                }
+              : undefined,
+          },
         },
-        birthPlaceName: birthLocation!.name,
-        currentPlaceName: currentLocation!.name,
-        currentLongitude: currentLocation!.longitude,
-        calcDate,
-        calcTime,
-        question,
-        hexagram: withHexagram && guaData
-          ? {
-              guaMark: guaData.result.guaMark,
-              guaTitle: guaData.result.guaTitle,
-              guaResult: guaData.result.guaResult,
-              guaChange: guaData.result.guaChange,
-            }
-          : undefined,
-      });
-
-      let ret = "";
-      for await (const delta of readStreamableValue(stream)) {
-        if (typeof delta === "string" && delta.startsWith(ERROR_PREFIX)) {
-          setError(delta.slice(ERROR_PREFIX.length));
-          return;
-        }
-        ret += delta ?? "";
-        setCompletion(ret);
-      }
+        setCompletion,
+      );
     } catch (e) {
       setError(e instanceof Error ? e.message : String(e));
     } finally {