docs(website): restructure documentation and move content to dedicated pages

- Split README.md into usage.md and library.md for better organization
- Move library section to its own page and update references
- Rename "Usage" section to "Examples" in README.md
- Update navigation links in base layout to reflect new structure
- Fix typo in function definition in image/README.md
- Add frontmatter to AGENTS.md for proper layout rendering
- Update footer link from GitHub to Codeberg

image/README.md

@@ -24,7 +24,7 @@ export CADDY_ROOT="_site" # default is path to the repo
 Run the tasfile.buld image:
 
 ```bash
-function run() {
+run() {
     echo "Open http://localhost:8080 in your browser"
     docker run -p 8080:80 \
         -e GIT_URL="$GIT_URL" \