Copy tx hash toast

[onyekachi66]

Closes #419

Description

Summary
This PR implements a more user‑friendly success state after a prediction is placed. It adds a "Copy" button next to the transaction hash on the success screen, allowing users to easily copy the hash to their clipboard with clear toast feedback.

Key Features & Changes

• Copy to Clipboard: Added a copy button in TxStatusTimeline.tsx for the transaction hash.
• Toast Notifications: Integrated the existing sonner toast library to provide immediate feedback (Transaction hash copied to clipboard).
• Graceful Fallbacks: Handles cases where clipboard access might be blocked or restricted (e.g., non-secure contexts) by showing an appropriate error toast.
• Explorer Link: The existing StellarExpert block explorer link remains fully functional alongside the new copy feature.

Files Modified

• src/components/TxStatusTimeline.tsx – Added copy handler, UI button, and toast integration.

Acceptance Criteria Met

• Offer Copy tx hash + toast after successful place_bet
• Optional explorer link included
• Clipboard works on secure context
• Failure toast if clipboard is blocked

---

[vercel]

@onyekachi66 is attempting to deploy a commit to the josephchimebuka's projects Team on Vercel.

A member of the Team first needs to authorize it.