docs: Update docs for the correctness (#13)

services/docs/content/en/root/reference/configure.md

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+---
+title: Configuration Actions
+description: Host provisioning, template engine, and system-level configuration.
+weight: 53
+---
+
+Configuration actions are used to provision the host and maintain system-level services. They rely heavily on the built-in template engine to generate declarative configuration files.
+
+## The Template Engine {#template-engine}
+
+The Root framework uses `envsubst` (from `gettext-base`) to render templates. This allows you to use standard Bash environment variables directly within your configuration files.
+
+### Template Conventions
+
+- **File Extension**: Templates typically use the `.template` extension (e.g., `crontab.template`).
+- **Variable Syntax**: Use `${VARIABLE_NAME}` or `$VARIABLE_NAME` to inject values.
+- **Auto-Discovery**: Many actions automatically look for templates in specific directories within the [Configs](/root/glossary#configs) repository.
+
+### Rendering Helpers
+
+The `root_template.sh` library provides several helpers:
+
+- `root_template_render <input> <output>`: Renders a single file.
+- `root_template_render_directory <src> <dest>`: Recursively renders an entire directory structure.
+- `root_template_crontab <template>`: Renders and installs a crontab for the current user.
+
+## Core Configuration Actions {#actions}
+
+| Action | Description |
+| :--- | :--- |
+| `configure/base` | Installs essential packages (`sudo`, `ufw`, `docker`) and sets up basic system users. |
+| `configure/cron` | Renders and installs node-specific crontabs. |
+| `configure/crowdsec` | Sets up the CrowdSec agent and bouncers. |
+| `configure/routing` | Configures system-level routing and bridge networks. |
+| `configure/systemd` | Installs and enables systemd service units. |
+| `configure/ufw` | Renders and applies firewall rules using UFW and `ufw-docker`. |
+
+## Example: Nginx Template {#example}
+
+```nginx filename="nginx.conf.template"
+# This template uses ROOT_NODE environment variable
+user  nginx;
+worker_processes  auto;
+
+error_log  /var/log/nginx/error.log notice;
+pid        /var/run/nginx.pid;
+
+events {
+    worker_connections  1024;
+}
+
+http {
+    include       /etc/nginx/mime.types;
+    default_type  application/octet-stream;
+    
+    # Injected from environment
+    server_name ${ROOT_NODE}.example.com;
+}
+```
+
+---
+
+**See also:**
+
+- [Concept: Infrastructure Architecture](/root/concepts/architecture)
+- [Reference: ROOT_ API Reference](/root/reference/root-api)