Show the current network connection status and RPC health in the UI.
Acceptance Criteria:
- Show green/red dot in Navbar indicating RPC connection status
- Display network name (Testnet/Mainnet) next to indicator
- Show warning banner when RPC is unreachable
- Auto-retry connection every 30 seconds
Files: new file src/components/ConnectionStatus.tsx, src/components/Navbar.tsx
Show the current network connection status and RPC health in the UI.
Acceptance Criteria:
Files: new file
src/components/ConnectionStatus.tsx,src/components/Navbar.tsx