feat: add AIHubMix provider (#865)

* feat: add AIHubMix provider

* feat: load AIHubMix models dynamically

* feat: polish AIHubMix model setup

* feat: send AIHubMix app code

* docs: remove redundant AIHubMix recommendation

---------

Co-authored-by: LL <13697272357@163.com>

app/api/aihubmix-models/route.ts

@@ -0,0 +1,61 @@
+import { NextResponse } from "next/server"
+import {
+    AIHUBMIX_MODELS_ENDPOINT,
+    extractAihubmixModelIds,
+} from "@/lib/aihubmix-models"
+import { SUGGESTED_MODELS } from "@/lib/types/model-config"
+
+const SUCCESS_CACHE_CONTROL =
+    "public, max-age=300, s-maxage=3600, stale-while-revalidate=86400"
+
+function fallbackResponse() {
+    return NextResponse.json(
+        {
+            models: SUGGESTED_MODELS.aihubmix || [],
+            source: "fallback",
+        },
+        {
+            headers: {
+                "Cache-Control": "no-store",
+            },
+        },
+    )
+}
+
+export async function GET() {
+    try {
+        const response = await fetch(AIHUBMIX_MODELS_ENDPOINT, {
+            next: { revalidate: 3600 },
+        })
+
+        if (!response.ok) {
+            console.warn(
+                `[aihubmix-models] Failed to fetch models: ${response.status}`,
+            )
+            return fallbackResponse()
+        }
+
+        const payload = await response.json()
+        const models = extractAihubmixModelIds(payload)
+
+        if (models.length === 0) {
+            console.warn("[aihubmix-models] Model list response was empty")
+            return fallbackResponse()
+        }
+
+        return NextResponse.json(
+            {
+                models,
+                source: "aihubmix",
+            },
+            {
+                headers: {
+                    "Cache-Control": SUCCESS_CACHE_CONTROL,
+                },
+            },
+        )
+    } catch (error) {
+        console.warn("[aihubmix-models] Failed to load models:", error)
+        return fallbackResponse()
+    }
+}