Update documentation and configuration for Realtime Agent Studio

- Revised mkdocs.yml to reflect the new site name and description, enhancing clarity for users.
- Added a changelog.md to document important changes and updates for the project.
- Introduced a roadmap.md to outline development plans and progress for future releases.
- Expanded index.md with a comprehensive overview of the platform, including core features and installation instructions.
- Enhanced concepts documentation with detailed explanations of assistants, engines, and their configurations.
- Updated configuration documentation to provide clear guidance on environment setup and service configurations.
- Added extra JavaScript for improved user experience in the documentation site.

docs/content/javascripts/extra.js

@@ -0,0 +1,26 @@
+// Realtime Agent Studio - Custom JavaScript
+
+document.addEventListener("DOMContentLoaded", function () {
+  // Add external link icons
+  document.querySelectorAll('a[href^="http"]').forEach(function (link) {
+    if (!link.hostname.includes(window.location.hostname)) {
+      link.setAttribute("target", "_blank");
+      link.setAttribute("rel", "noopener noreferrer");
+    }
+  });
+
+  // Smooth scroll for anchor links
+  document.querySelectorAll('a[href^="#"]').forEach(function (anchor) {
+    anchor.addEventListener("click", function (e) {
+      const targetId = this.getAttribute("href").slice(1);
+      const targetElement = document.getElementById(targetId);
+      if (targetElement) {
+        e.preventDefault();
+        targetElement.scrollIntoView({
+          behavior: "smooth",
+          block: "start",
+        });
+      }
+    });
+  });
+});