feat: Implement collection deletion and loading spinners

- Add API endpoint and handler to delete collections
- Introduce LoadingSpinner component for async operations
- Show loading spinners during file loading and preview rendering
- Enhance modal accessibility by removing aria-hidden attribute
- Refactor delete functionality to distinguish between collections and files/folders
- Remove unused collection definitions from config

collections/documents/getting_started/hero_docker.md

@@ -0,0 +1,67 @@
+You can build Hero as a Docker container.
+
+The code is availabe at this [open-source repository](https://github.com/mik-tf/hero-container).
+
+## Prerequisites
+
+- Docker installed on your system (More info [here](https://manual.grid.tf/documentation/system_administrators/computer_it_basics/docker_basics.html#install-docker-desktop-and-docker-engine))
+- SSH keys for deploying Hero websites (if publishing)
+
+## Build the Image
+
+- Clone the repository
+
+    ```
+    git clone https://github.com/mik-tf/hero-container
+    cd hero-container
+    ```
+
+- Build the Docker image:
+
+    ```bash
+    docker build -t heroc .
+    ```
+
+## Pull the Image from Docker Hub
+
+If you don't want to build the image, you can pull it from Docker Hub.
+
+```
+docker pull logismosis/heroc
+```
+
+In this case, use `logismosi/heroc` instead of `heroc` to use the container.
+
+## Run the Hero Container
+
+You can run the container with an interactive shell:
+
+```bash
+docker run -it heroc
+```
+
+You can run the container with an interactive shell, while setting the host as your local network, mounting your current directory as the workspace and adding your SSH keys:
+
+```bash
+docker run --network=host \
+  -v $(pwd):/workspace \
+  -v ~/.ssh:/root/ssh \
+  -it heroc
+```
+
+By default, the container will:
+
+- Start Redis server in the background
+- Copy your SSH keys to the proper location
+- Initialize the SSH agent
+- Add your default SSH key (`id_ed25519`)
+
+To use a different SSH key, specify it with the KEY environment variable (e.g. `KEY=id_ed25519`):
+
+```bash
+docker run --network=host \
+  -v $(pwd):/workspace \
+  -v ~/.ssh:/root/ssh \
+  -e KEY=your_custom_key_name \
+  -it heroc
+```