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/bazi-form.tsx

@@ -1,7 +1,6 @@
 "use client";
 
 import { useState } from "react";
-import { readStreamableValue } from "ai/rsc";
 import { BrainCircuit } from "lucide-react";
 import { Button } from "@/components/ui/button";
 import { Textarea } from "@/components/ui/textarea";
@@ -12,8 +11,7 @@ import RegionSelect, {
   useRegionLocation,
 } from "@/components/shared/region-select";
 import { calculateBazi, type BaziChart } from "@/lib/calc/bazi";
-import { getBaziAnswer } from "@/app/actions/bazi";
-import { ERROR_PREFIX } from "@/lib/constant";
+import { streamAiCompletion } from "@/lib/ai/client-stream";
 
 export default function BaziForm() {
   const [date, setDate] = useState(nowDateString());
@@ -70,20 +68,17 @@ export default function BaziForm() {
     setIsLoading(true);
     setShowAi(true);
     try {
-      const stream = await getBaziAnswer(
-        input,
-        question,
-        location!.name,
+      await streamAiCompletion(
+        {
+          mode: "bazi",
+          payload: {
+            input,
+            question,
+            birthPlaceName: location!.name,
+          },
+        },
+        setCompletion,
       );
-      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);
-      }
     } catch (err) {
       setError(err instanceof Error ? err.message : String(err));
     } finally {