feat(server): add LISTEN_ADDR env var for allowing server to listen on ipv6 (#14211)

The old code hardcoded 0.0.0.0 which means the server only listened for
ipv4 connections, making it not work on ipv6-only networks.

This change adds a LISTEN_ADDR env var which allows the server to bind
to ipv6 as well.

<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->
## Summary by CodeRabbit

* **New Features**
* Server listen address is now configurable via the LISTEN_ADDR
environment variable (default: 0.0.0.0), enabling IPv4/IPv6 or
interface-specific binding.
* Configuration schemas and admin UI now expose the listen address
option so deployments can view and override it.

<sub>✏️ Tip: You can customize this high-level summary in your review
settings.</sub>
<!-- end of auto-generated comment: release notes by coderabbit.ai -->

packages/backend/server/src/core/config/config.ts

@@ -13,6 +13,7 @@ declare global {
       https: boolean;
       host: string;
       hosts: ConfigItem<string[]>;
+      listenAddr: string;
       port: number;
       path: string;
       name?: string;
@@ -58,6 +59,11 @@ Default to be \`[server.protocol]://[server.host][:server.port]\` if not specifi
     default: [],
     shape: z.array(z.string()),
   },
+  listenAddr: {
+    desc: 'The address to listen on (e.g., 0.0.0.0 for IPv4, :: for IPv6).',
+    default: '0.0.0.0',
+    env: 'LISTEN_ADDR',
+  },
   port: {
     desc: 'Which port the server will listen on.',
     default: 3010,

packages/backend/server/src/server.ts

@@ -75,11 +75,14 @@ export async function run() {
   }
 
   const url = app.get(URLHelper);
-  const listeningHost = '0.0.0.0';
 
-  await app.listen(config.server.port, listeningHost);
+  await app.listen(config.server.port, config.server.listenAddr);
+
+  const formattedAddr = config.server.listenAddr.includes(':')
+    ? `[${config.server.listenAddr}]`
+    : config.server.listenAddr;
 
   logger.log(`AFFiNE Server is running in [${env.DEPLOYMENT_TYPE}] mode`);
-  logger.log(`Listening on http://${listeningHost}:${config.server.port}`);
+  logger.log(`Listening on http://${formattedAddr}:${config.server.port}`);
   logger.log(`And the public server should be recognized as ${url.baseUrl}`);
 }

packages/frontend/admin/src/config.json

@@ -216,6 +216,11 @@
       "type": "Array",
       "desc": "Multiple hosts the server will accept requests from."
     },
+    "listenAddr": {
+      "type": "String",
+      "desc": "The address to listen on (e.g., 0.0.0.0 for IPv4, :: for IPv6).",
+      "env": "LISTEN_ADDR"
+    },
     "port": {
       "type": "Number",
       "desc": "Which port the server will listen on.",