feat: add CopyButton component and copy-to-clipboard across dashboard

New reusable CopyButton component with checkmark feedback after copy.

Added copy buttons to:
- SSH public key display (add repo modal)
- Webhook URL field (edit repo modal)
- Webhook secret field (edit repo modal)
- Code snippets in finding detail (via enhanced CodeSnippet component)
- Suggested fix code blocks
- MCP server endpoint URLs

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

compliance-dashboard/src/components/copy_button.rs

@@ -0,0 +1,45 @@
+use dioxus::prelude::*;
+use dioxus_free_icons::icons::bs_icons::*;
+use dioxus_free_icons::Icon;
+
+/// A small copy-to-clipboard button that shows a checkmark after copying.
+///
+/// Usage: `CopyButton { value: "text to copy" }`
+#[component]
+pub fn CopyButton(value: String, #[props(default = false)] small: bool) -> Element {
+    let mut copied = use_signal(|| false);
+
+    let size = if small { 12 } else { 14 };
+    let class = if small {
+        "copy-btn copy-btn-sm"
+    } else {
+        "copy-btn"
+    };
+
+    rsx! {
+        button {
+            class: class,
+            title: if copied() { "Copied!" } else { "Copy to clipboard" },
+            onclick: move |_| {
+                let val = value.clone();
+                // Escape single quotes for JS
+                let escaped = val.replace('\\', "\\\\").replace('\'', "\\'");
+                let js = format!("navigator.clipboard.writeText('{escaped}')");
+                document::eval(&js);
+                copied.set(true);
+                spawn(async move {
+                    #[cfg(feature = "web")]
+                    gloo_timers::future::TimeoutFuture::new(2000).await;
+                    #[cfg(not(feature = "web"))]
+                    tokio::time::sleep(std::time::Duration::from_secs(2)).await;
+                    copied.set(false);
+                });
+            },
+            if copied() {
+                Icon { icon: BsCheckLg, width: size, height: size }
+            } else {
+                Icon { icon: BsClipboard, width: size, height: size }
+            }
+        }
+    }
+}