feat: UI improvements with icons, back navigation, and overview cards

- Move AI Chat and MCP Servers from sidebar to overview page as cards
- Remove Graph from sidebar (accessible from repositories page)
- Add back buttons to all drill-down pages (finding detail, graph, chat, etc.)
- Replace text labels with icons + tooltips on action buttons and status badges
- Improve spacing and margins across tables and cards

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

compliance-dashboard/src/pages/dast_targets.rs

@@ -1,4 +1,6 @@
 use dioxus::prelude::*;
+use dioxus_free_icons::icons::bs_icons::*;
+use dioxus_free_icons::Icon;
 
 use crate::components::page_header::PageHeader;
 use crate::components::toast::{ToastType, Toasts};
@@ -14,6 +16,15 @@ pub fn DastTargetsPage() -> Element {
     let mut new_url = use_signal(String::new);
 
     rsx! {
+        div { class: "back-nav",
+            button {
+                class: "btn btn-ghost btn-back",
+                onclick: move |_| { navigator().go_back(); },
+                Icon { icon: BsArrowLeft, width: 16, height: 16 }
+                "Back"
+            }
+        }
+
         PageHeader {
             title: "DAST Targets",
             description: "Configure target applications for dynamic security testing",