fix: copy button functionality in web browsers

- Add clipboard utility with fallback for non-secure contexts
- Implement modern Clipboard API with document.execCommand fallback
- Update copy buttons in code blocks, markdown, messages, and session list
- Add proper error handling and user feedback for copy operations

Fixes issue where copy buttons did not work in web browsers served over HTTP or without Clipboard API support

packages/ui/src/components/session-list.tsx

@@ -10,6 +10,7 @@ import { formatShortcut } from "../lib/keyboard-utils"
 import { showToastNotification } from "../lib/notifications"
 import { deleteSession, loading, renameSession } from "../stores/sessions"
 import { getLogger } from "../lib/logger"
+import { copyToClipboard } from "../lib/clipboard"
 const log = getLogger("session")
 
 
@@ -72,14 +73,14 @@ const SessionList: Component<SessionListProps> = (props) => {
  
   const copySessionId = async (event: MouseEvent, sessionId: string) => {
     event.stopPropagation()
- 
+
     try {
-      if (typeof navigator === "undefined" || !navigator.clipboard) {
-        throw new Error("Clipboard API unavailable")
+      const success = await copyToClipboard(sessionId)
+      if (success) {
+        showToastNotification({ message: "Session ID copied", variant: "success" })
+      } else {
+        showToastNotification({ message: "Unable to copy session ID", variant: "error" })
       }
- 
-      await navigator.clipboard.writeText(sessionId)
-      showToastNotification({ message: "Session ID copied", variant: "success" })
     } catch (error) {
       log.error(`Failed to copy session ID ${sessionId}:`, error)
       showToastNotification({ message: "Unable to copy session ID", variant: "error" })