fix: update INTERNAL_HOST in .env.example and config to use 0.0.0.0 instead of [::]

Author: LuggaPugga

apps/backend/.env.example

@@ -9,6 +9,6 @@ S3_ACCESS_KEY_ID=
 S3_SECRET_ACCESS_KEY=
 HOST=0.0.0.0
 PORT=3000
-INTERNAL_HOST=[::]
+INTERNAL_HOST=0.0.0.0
 INTERNAL_PORT=9485
 ADMIN_TOKEN=replace-with-long-random-token

apps/backend/src/config.rs

@@ -23,7 +23,7 @@ impl Config {
             .unwrap_or_else(|_| "3000".into())
             .parse()
             .expect("PORT must be a valid u16");
-        let internal_host = std::env::var("INTERNAL_HOST").unwrap_or_else(|_| "[::]".into());
+        let internal_host = std::env::var("INTERNAL_HOST").unwrap_or_else(|_| "0.0.0.0".into());
         let internal_port: u16 = std::env::var("INTERNAL_PORT")
             .unwrap_or_else(|_| "3001".into())
             .parse()