fix: add transaction feedback toasts and trade panel error boundary (…

[Alaka-ibr]

Description

Closes #546

This PR introduces visual transaction feedback toasts following confirmed buy and sell trades, and wraps the trade panel in a React Error Boundary to isolate render errors without crashing the surrounding page.

Changes Made

• Transaction Success Toasts:

  • Displays Bought {n} key{s} from {creator} after a buy confirmation.
  • Displays Sold {n} key{s} from {creator} after a sell confirmation.
  • Formats quantity singular vs. plural appropriately (1 key vs 2 keys).
  • Configured success toasts to auto-dismiss after 4 seconds (4,000ms).

• Trade Panel Error Boundary:

  • Created TradePanelErrorBoundary class component to catch unexpected render errors inside the trade dialog.
  • Displays an inline fallback UI with an error message and a Retry button.
  • Clicking Retry resets the error boundary state and remounts the trade panel cleanly.
  • Ensures header, creator grid, holdings overview, and timeline remain mounted and functional during a trade panel failure.

• Tests:

  • Added unit test suite in TradePanelErrorBoundary.test.tsx covering normal child rendering, fallback UI on render error, layout isolation, and state reset on retry.
  • Updated integration tests in LandingPage.tradeConfirmToast.integration.test.tsx, LandingPage.buyFlowEndToEnd.integration.test.tsx, and LandingPage.sellFlow.integration.test.tsx to verify new toast messages and boundary behaviors.

How Has This Been Tested?

Ran local Vitest suite across target test files:

• src/components/common/__tests__/TradePanelErrorBoundary.test.tsx
• src/pages/__tests__/LandingPage.tradeConfirmToast.integration.test.tsx
• src/pages/__tests__/LandingPage.buyFlowEndToEnd.integration.test.tsx
• src/pages/__tests__/LandingPage.sellFlow.integration.test.tsx

All 13 unit and integration tests passed cleanly.

[Alaka-ibr]

Done, please review.

[Chucks1093]

Good work