Fix branch references in documentation

Update all GitHub URLs from 'main' to 'stable' branch in:
- README.md: Updated download URLs in Quick Start section
- docs/index.html: Updated curl command in installation instructions

This aligns the documentation with the stable branch deployment.

Author: franckferman

README.md

@@ -21,17 +21,17 @@ For Ubuntu Desktop, see: [github.com/franckferman/ubuntu-post-install](https://g
 ### Download and Run
 ```bash
 # Download script
-curl -O https://raw.githubusercontent.com/franckferman/debian-server-post-install/main/debian-server-post-install.sh
+curl -O https://raw.githubusercontent.com/franckferman/debian-server-post-install/stable/debian-server-post-install.sh
 chmod +x debian-server-post-install.sh
 
 # Or direct execution (basic profile only - review first!)
-curl -fsSL https://raw.githubusercontent.com/franckferman/debian-server-post-install/main/debian-server-post-install.sh | bash
+curl -fsSL https://raw.githubusercontent.com/franckferman/debian-server-post-install/stable/debian-server-post-install.sh | bash
 
 # For root users (add --allow-root)
 ./debian-server-post-install.sh --allow-root
 
 # Direct with arguments (download first)
-curl -fsSL https://raw.githubusercontent.com/franckferman/debian-server-post-install/main/debian-server-post-install.sh | bash -s -- --server-profile dev
+curl -fsSL https://raw.githubusercontent.com/franckferman/debian-server-post-install/stable/debian-server-post-install.sh | bash -s -- --server-profile dev
 ```
 
 ### Profile Examples

docs/index.html

@@ -383,7 +383,7 @@ <h2 class="section-title">Deploy in one command.</h2>
 
   <div style="position: relative; margin: 2rem 0; border-radius: 8px; overflow: hidden;">
 <pre style="background: var(--bg2); border: 1px solid var(--border); padding: 1.5rem; font-family: var(--mono); font-size: 0.8rem; line-height: 1.6; overflow-x: auto; white-space: pre-wrap;"># Download and make executable
-curl -O https://raw.githubusercontent.com/franckferman/debian-server-post-install/main/debian-server-post-install.sh
+curl -O https://raw.githubusercontent.com/franckferman/debian-server-post-install/stable/debian-server-post-install.sh
 chmod +x debian-server-post-install.sh
 
 # Review (important!)