feat: store node logo/favicon in postgres instead of S3

- Add logoData and faviconData columns to nodes table
- Create /api/admin/node/upload endpoint for direct DB storage
- Create /api/node/logo and /api/node/favicon endpoints to serve images
- Update admin page to use new upload endpoint
- Remove dependency on admin's personal S3 storage for node assets

src/app/api/node/favicon/route.ts

@@ -0,0 +1,60 @@
+import { NextResponse } from 'next/server';
+import { db, nodes } from '@/db';
+import { eq } from 'drizzle-orm';
+
+export const dynamic = 'force-dynamic';
+
+export async function GET() {
+  try {
+    if (!db) {
+      return NextResponse.json({ error: 'Database not available' }, { status: 500 });
+    }
+
+    const domain = process.env.NEXT_PUBLIC_NODE_DOMAIN || 'localhost:3000';
+
+    // 1. Try exact match
+    let node = await db.query.nodes.findFirst({
+      where: eq(nodes.domain, domain),
+    });
+
+    // 2. Fallback: If not found, check if there is exactly ONE node in the system
+    if (!node) {
+      const allNodes = await db.query.nodes.findMany({ limit: 2 });
+      if (allNodes.length === 1) {
+        node = allNodes[0];
+      }
+    }
+
+    // Check if we have favicon data
+    if (!node?.faviconData) {
+      return NextResponse.json({ error: 'Favicon not found' }, { status: 404 });
+    }
+
+    // Parse the data URL to extract MIME type and base64 data
+    const dataUrl = node.faviconData;
+    const match = dataUrl.match(/^data:([^;]+);base64,(.+)$/);
+
+    if (!match) {
+      // If not a proper data URL, try to serve as-is (backward compatibility)
+      return NextResponse.json({ error: 'Invalid favicon data' }, { status: 500 });
+    }
+
+    const mimeType = match[1];
+    const base64Data = match[2];
+    const buffer = Buffer.from(base64Data, 'base64');
+
+    // Return the image with proper headers
+    return new NextResponse(buffer, {
+      status: 200,
+      headers: {
+        'Content-Type': mimeType,
+        'Cache-Control': 'public, max-age=3600, stale-while-revalidate=86400',
+        'Content-Length': buffer.length.toString(),
+      },
+    });
+
+  } catch (error) {
+    console.error('Favicon serve error:', error);
+    return NextResponse.json({ error: 'Failed to serve favicon' }, { status: 500 });
+  }
+}