Add read-only Tron (TRC20) chain family support (#9)

* Add read-only Tron (TRC20) chain family support

Adds Tron as a third chain family alongside Substrate and EVM:
address derivation (BIP44 coin type 195, secp256k1 reused from the
existing Ethereum path, Base58Check encoding), TronGrid-backed TRX
and TRC20 USDT balance display, and a Room migration for the new
per-account Tron key/address columns. Read-only only — no send,
signing, or broadcast support yet.

* fix: exhaustive when branches for Trc20/TronNative asset types

ChainExt.kt's onChainAssetId and Common.kt's existentialDepositError
both switch exhaustively over Chain.Asset.Type and didn't have cases
for the new Trc20/TronNative variants, breaking compilation. Trc20
mirrors EvmErc20 (contract address as the on-chain id, dust burns
rather than transfers on removal); TronNative mirrors EvmNative.

README.md

@@ -2,7 +2,7 @@
 
 Next generation mobile wallet for Pezkuwichain and the Polkadot ecosystem.
 
-[![](https://img.shields.io/twitter/follow/pezkuwichain?label=Follow&style=social)](https://twitter.com/pezkuwichain)
+[![](https://img.shields.io/twitter/follow/pezkuwichain?label=Follow&style=social)](https://x.com/bizinikiwi)
 
 ## About
 
@@ -105,8 +105,8 @@ WALLET_CONNECT_PROJECT_ID=mock
 
 - Website: https://pezkuwichain.io
 - Documentation: https://docs.pezkuwichain.io
-- Telegram: https://t.me/pezkuwichain
-- Twitter: https://twitter.com/pezkuwichain
+- Telegram: https://t.me/kurdishmedya
+- Twitter: https://x.com/bizinikiwi
 - GitHub: https://github.com/pezkuwichain
 
 ## License