docs: update TransactionDetail screen map with new fields

Add Type, Token contract, Block, Nonce, Transaction fee, Gas price,
and Gas used fields to the TransactionDetail section in the README
screen map to match the implemented UI.

README.md

@@ -437,6 +437,10 @@ transitions.
 - **When**: User tapped a transaction row from AddressDetail or AddressToken.
 - **Elements**:
     - "Transaction" heading, "Back" button
+    - Type: transaction classification — one of: Native ETH Transfer, ERC-20
+      Token Transfer, Swap, Token Approval, Contract Call, Contract Creation
+    - Token contract: shown for ERC-20 transfers — color dot + full contract
+      address (tap to copy) + etherscan token link
     - Status: "Success" or "Failed"
     - Time: ISO datetime + relative age in parentheses
     - Amount: value + symbol (bold)
@@ -445,6 +449,11 @@ transitions.
     - To: blockie + color dot + full address (tap to copy) + etherscan link
         - ENS name if available
     - Transaction hash: full hash (tap to copy) + etherscan link
+    - Block: block number (tap to copy) + etherscan block link
+    - Nonce: transaction nonce (tap to copy)
+    - Transaction fee: ETH amount (tap to copy)
+    - Gas price: value in Gwei (tap to copy)
+    - Gas used: integer (tap to copy)
 - **Transitions**:
     - "Back" → **AddressToken** (if `selectedToken` set) or **AddressDetail**