Bitget v2 WS requires a text message "ping" every 30s, not a WebSocket
PingMessage control frame (opcode 0x9). Using the wrong ping type caused
a silent failure: connection stays up and subscription succeeds, but NO
ticker data is pushed — zero errors, zero reconnection logs.
Changes:
- connector.go: Add TextPing bool flag, send text 'ping' when set
- bitget.go: Set TextPing=true, handle text 'pong', add debug logging
- scanner.go: Expand to 179 overlapping Bitget+HL coins