Document locale and editor override in README and DOCKER_HUB

DOCKER_HUB.md

@@ -114,6 +114,25 @@ The entrypoint automatically detects the owner of `/workspace` and adjusts the c
 | `USER_UID` | Container user UID | Auto-detect from `/workspace` owner |
 | `USER_GID` | Container user GID | Auto-detect from `/workspace` owner |
 
+### Locale and Editor
+
+The container defaults to English (`en_US.UTF-8`) and neovim as the editor. Override via environment variables:
+
+| Variable | Description | Default |
+|---|---|---|
+| `LANG` | System locale | `en_US.UTF-8` |
+| `LANGUAGE` | Language priority list | `en_US:en` |
+| `LC_ALL` | Override all locale settings | `en_US.UTF-8` |
+| `EDITOR` | Default text editor | `nvim` |
+
+All common UTF-8 locales are pre-generated in the image. Example for Swedish:
+
+```bash
+LANG=sv_SE.UTF-8
+LANGUAGE=sv_SE:sv
+LC_ALL=sv_SE.UTF-8
+```
+
 ## Initial Setup
 
 ### 1. Create host directories

README.md

@@ -117,6 +117,10 @@ docker compose exec -u developer devbox aws --version
 | `SSH_KEY_PATH` | Host SSH key directory | `~/.ssh` |
 | `USER_UID` | Override container user UID | Auto-detect from `/workspace` |
 | `USER_GID` | Override container user GID | Auto-detect from `/workspace` |
+| `LANG` | System locale | `en_US.UTF-8` |
+| `LANGUAGE` | Language priority list | `en_US:en` |
+| `LC_ALL` | Override all locale settings | `en_US.UTF-8` |
+| `EDITOR` | Default text editor | `nvim` |
 | `ENABLE_OMOS` | Enable oh-my-opencode-slim multi-agent orchestration | `false` |
 | `OMOS_TMUX` | Enable tmux pane integration for OMOS | `false` |
 | `OMOS_SKILLS` | Install OMOS recommended skills on first run | `true` |