Add Tron (TRC20/TRX) send/transfer support

Reuses the existing generic fee-sufficiency validation
(sufficientTransferableBalanceToPayOriginFee) and send flow
unchanged. Transaction construction goes through TronGrid's own
createtransaction/triggersmartcontract endpoints (verified live
against Shasta testnet) rather than a hand-rolled protobuf
implementation; signing reuses the existing secp256k1 path
(SignerPayloadRaw.skipMessageHashing) already used for Ethereum,
no new crypto library. Also fixes a Phase 1 gap: Chain.isValidAddress()
had no isTronBased branch, so every Tron send would have failed
address validation.

No Energy staking/delegation/rental UI - only Tron's default
protocol behavior (burn TRX to cover Bandwidth/Energy shortfall).

common/src/main/java/io/novafoundation/nova/common/utils/TronAddress.kt

@@ -2,6 +2,7 @@ package io.novafoundation.nova.common.utils
 
 import io.novasama.substrate_sdk_android.extensions.asEthereumPublicKey
 import io.novasama.substrate_sdk_android.extensions.toAccountId
+import io.novasama.substrate_sdk_android.extensions.toHexString
 import io.novasama.substrate_sdk_android.runtime.AccountId
 import java.math.BigInteger
 
@@ -113,3 +114,21 @@ fun String.tronAddressToAccountId(): AccountId {
 fun String.isValidTronAddress(): Boolean = runCatching { tronAddressToAccountId() }.isSuccess
 
 fun emptyTronAccountId() = ByteArray(20) { 1 }
+
+/**
+ * Hex form of a Tron address (`0x41` prefix byte ++ accountId, hex-encoded, no `0x` prefix), e.g.
+ * `41a614f803b6fd780986a42c78ec9c7f77e6ded13c`. This is the format TronGrid's `/wallet/*` transaction
+ * construction/broadcast endpoints expect when called with `"visible": false` (as opposed to the human-facing
+ * Base58Check form used by the `/v1/accounts/{address}` balance endpoint and by [toTronAddress]).
+ */
+fun AccountId.toTronHexAddress(): String {
+    require(size == 20) { "Tron account id must be 20 bytes, got $size" }
+
+    return byteArrayOf(TRON_ADDRESS_PREFIX_BYTE).toHexString(withPrefix = false) + toHexString(withPrefix = false)
+}
+
+/**
+ * Converts a human-facing Base58Check Tron address (e.g. a TRC20 `contractAddress` from chain config) directly
+ * into the hex form described in [toTronHexAddress].
+ */
+fun String.tronAddressToHexAddress(): String = tronAddressToAccountId().toTronHexAddress()

common/src/test/java/io/novafoundation/nova/common/utils/TronAddressTest.kt

@@ -44,6 +44,18 @@ class TronAddressTest {
         assertTrue(decodedBack.contentEquals(accountId))
     }
 
+    @Test
+    fun `toTronHexAddress should produce the known hex form`() {
+        val accountId = knownTronAddressHex.fromHex().copyOfRange(1, 21)
+
+        assertEquals(knownTronAddressHex, accountId.toTronHexAddress())
+    }
+
+    @Test
+    fun `tronAddressToHexAddress should produce the known hex form directly from a Base58 address`() {
+        assertEquals(knownTronAddressHex, knownTronAddress.tronAddressToHexAddress())
+    }
+
     @Test
     fun `isValidTronAddress should accept known good address`() {
         assertTrue(knownTronAddress.isValidTronAddress())