docs: add pixi installation instructions

Add prerequisites section to README with pixi install command.
Expand installation.md with platform-specific tabs and link to
official pixi documentation.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: jayhesselberth

README.md

@@ -8,6 +8,16 @@ A Snakemake pipeline to process ONT aa-tRNA-seq data.
 
 **[Documentation](https://rnabioco.github.io/aa-tRNA-seq-pipeline)** | **[Downstream Analysis](https://github.com/rnabioco/aa-tRNA-seq)**
 
+## Prerequisites
+
+This pipeline uses [Pixi](https://pixi.sh) for environment management. Install it first:
+
+```bash
+curl -fsSL https://pixi.sh/install.sh | sh
+```
+
+See the [Pixi installation guide](https://pixi.prefix.dev/latest/installation/) for alternative methods (Homebrew, Windows, etc.).
+
 ## Usage
 
 The pipeline can be configured by editing the `config/config.yml` file. The config file specifications will

docs/getting-started/installation.md

@@ -11,18 +11,34 @@ This guide covers installing the aa-tRNA-seq pipeline and its dependencies.
 
 ## Install Pixi
 
-The pipeline uses [Pixi](https://pixi.sh) for environment management. Install it with:
+The pipeline uses [Pixi](https://pixi.sh) for environment management.
 
-```bash
-curl -fsSL https://pixi.sh/install.sh | bash
-```
+=== "Linux/macOS"
+
+    ```bash
+    curl -fsSL https://pixi.sh/install.sh | sh
+    ```
+
+=== "macOS (Homebrew)"
+
+    ```bash
+    brew install pixi
+    ```
+
+=== "Windows"
+
+    ```powershell
+    powershell -ExecutionPolicy Bypass -c "irm -useb https://pixi.sh/install.ps1 | iex"
+    ```
 
 After installation, restart your shell or run:
 
 ```bash
-source ~/.bashrc  # or ~/.zshrc
+source ~/.bashrc  # or ~/.zshrc for Zsh
 ```
 
+For additional installation options, see the [official Pixi installation guide](https://pixi.prefix.dev/latest/installation/).
+
 ## Clone the Repository
 
 ```bash