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

_includes/layouts/base.njk

@@ -29,18 +29,18 @@
         </ul>
         <ul>
           <li><a class="contrast" href="/#specification">Specification</a></li>
-          <li><a class="contrast" href="/#usage">Usage</a></li>
-          <li><a class="contrast" href="/#naming">Naming</a></li>
-          <li><a class="contrast" href="/#patterns">Patterns</a></li>
-          <li><a class="contrast" href="/#example">Example</a></li>
-          <li><a class="contrast" href="/#library">Library</a></li>
+          <li><a class="contrast" href="/usage/">Usage</a></li>
+          <li><a class="contrast" href="/usage/#naming">Naming</a></li>
+          <li><a class="contrast" href="/usage/#patterns">Patterns</a></li>
+          <li><a class="contrast" href="/#examples">Examples</a></li>
+          <li><a class="contrast" href="/library">Library</a></li>
         </ul>
       </nav>
       <article>
         {{ content | safe }}
       </article>
       <footer>
-        <a href="https://codeberg.org/janikvonrotz/taskfile.build/_edit/main/{{ page.inputPath }}">Edit this page on GitHub</a>
+        <a href="https://codeberg.org/janikvonrotz/taskfile.build/_edit/main/{{ page.inputPath }}">Edit this page on Codeberg</a>
       </footer>
     </main>
     <script src="/js/randomFunctionNames.js"></script>