Replace Python server with JDK's jwebserver

Co-authored-by: brunoborges <129743+brunoborges@users.noreply.github.com>

Author: Copilot

.github/copilot-instructions.md

@@ -119,6 +119,6 @@ Each `content/category/slug.json` file has this structure:
 ## Local Development
 
 ```bash
-java -jar html-generators/generate.jar              # Build HTML pages + snippets.json
-python3 -m http.server -d site 8090  # Serve locally
+java -jar html-generators/generate.jar  # Build HTML pages + snippets.json
+jwebserver -d site -p 8090              # Serve locally
 ```

README.md

@@ -56,7 +56,7 @@ Generated files (`site/category/*.html` and `site/data/snippets.json`) are in `.
 java -jar html-generators/generate.jar
 
 # Serve locally
-python3 -m http.server -d site 8090
+jwebserver -d site -p 8090
 # Open http://localhost:8090
 ```