reorder transaction detail view: txid first, logical grouping with separators

Reorganize the transaction detail view into logical blocks separated by
thin horizontal rules:

- Identity: transaction hash (first!), type, status
- Timing: time, block number
- Value: amount, native quantity, token contract, from, to
- Decoded details: action/protocol/steps (contract calls)
- Network details: nonce, gas price, gas used, fee
- Raw data: full calldata

Updates README screen map to reflect new field ordering and grouping.

closes #131

README.md

@@ -439,9 +439,8 @@ transitions.
     - "Transaction" heading, "Back" button
     - **Identity block**:
         - Transaction hash: full hash (tap to copy) + etherscan link
-        - Type: transaction classification — one of: Native ETH Transfer,
-          ERC-20 Token Transfer, Swap, Token Approval, Contract Call,
-          Contract Creation
+        - Type: transaction classification — one of: Native ETH Transfer, ERC-20
+          Token Transfer, Swap, Token Approval, Contract Call, Contract Creation
         - Status: "Success" or "Failed"
     - **Timing block**:
         - Time: ISO datetime + relative age in parentheses
@@ -449,12 +448,12 @@ transitions.
     - **Value block**:
         - Amount: value + symbol (bold)
         - Native quantity: raw integer + unit (shown when available)
-        - Token contract: shown for ERC-20 transfers — color dot + full
-          contract address (tap to copy) + etherscan token link
+        - Token contract: shown for ERC-20 transfers — color dot + full contract
+          address (tap to copy) + etherscan token link
         - From: blockie + color dot + full address (tap to copy) + etherscan
           link; ENS name if available
-        - To: blockie + color dot + full address (tap to copy) + etherscan
-          link; ENS name if available
+        - To: blockie + color dot + full address (tap to copy) + etherscan link;
+          ENS name if available
     - **Decoded details** (shown for contract calls):
         - Action name, decoded parameters, token details, swap steps
     - **Network details** (shown when on-chain data is available):