feat(config-route): add POST handler

src/app/api/config/route.ts

@@ -2,6 +2,11 @@ import configManager from '@/lib/config';
 import ModelRegistry from '@/lib/models/registry';
 import { NextRequest, NextResponse } from 'next/server';
 
+type SaveConfigBody = {
+  key: string;
+  value: string;
+};
+
 export const GET = async (req: NextRequest) => {
   try {
     const values = configManager.currentConfig;
@@ -11,19 +16,53 @@ export const GET = async (req: NextRequest) => {
     const modelProviders = await modelRegistry.getActiveProviders();
 
     values.modelProviders = values.modelProviders.map((mp) => {
-      const activeProvider = modelProviders.find((p) => p.id === mp.id)
+      const activeProvider = modelProviders.find((p) => p.id === mp.id);
 
       return {
         ...mp,
         chatModels: activeProvider?.chatModels ?? mp.chatModels,
-        embeddingModels: activeProvider?.embeddingModels ?? mp.embeddingModels
-      }
-    })
+        embeddingModels: activeProvider?.embeddingModels ?? mp.embeddingModels,
+      };
+    });
 
     return NextResponse.json({
       values,
       fields,
-    })
+    });
+  } catch (err) {
+    console.error('Error in getting config: ', err);
+    return Response.json(
+      { message: 'An error has occurred.' },
+      { status: 500 },
+    );
+  }
+};
+
+export const POST = async (req: NextRequest) => {
+  try {
+    const body: SaveConfigBody = await req.json();
+
+    if (!body.key || !body.value) {
+      return Response.json(
+        {
+          message: 'Key and value are required.',
+        },
+        {
+          status: 400,
+        },
+      );
+    }
+
+    configManager.updateConfig(body.key, body.value);
+
+    return Response.json(
+      {
+        message: 'Config updated successfully.',
+      },
+      {
+        status: 200,
+      },
+    );
   } catch (err) {
     console.error('Error in getting config: ', err);
     return Response.json(