feat: add blockie identicon to Identity block in TransactionDetail

Generate a blockie from the transaction hash and display it centered
at the top of the Identity block, matching the pattern used in
AddressDetail and AddressToken views. Updates README to document
the new element.

README.md

@@ -439,14 +439,11 @@ transitions.
   matching the Settings view pattern):
     - "Transaction" heading, "Back" button
     - **Identity block**:
+        - Blockie identicon (48px, centered, derived from transaction hash)
         - 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
         - Status: "Success" or "Failed"
-        - 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
     - **Timing block**:
         - Time: ISO datetime + relative age in parentheses
         - Block: block number (tap to copy) + etherscan block link
@@ -455,6 +452,10 @@ transitions.
         - 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
+        - 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
     - **Decoded details** (shown for contract calls):
         - Action name, decoded parameters, token details, swap steps
     - **Network details** (shown when on-chain data is available):

src/popup/index.html

@@ -1068,6 +1068,10 @@
                 <!-- ── Identity ── -->
                 <div class="bg-well p-3 mx-1 mb-3">
                     <h3 class="font-bold mb-1">Identity</h3>
+                    <div
+                        id="tx-detail-blockie"
+                        class="flex justify-center mt-1 mb-3"
+                    ></div>
                     <div class="mb-2">
                         <div class="text-xs text-muted mb-1">
                             Transaction hash
@@ -1088,17 +1092,6 @@
                         <div class="text-xs text-muted mb-1">Status</div>
                         <div id="tx-detail-status" class="text-xs"></div>
                     </div>
-                    <div class="mb-2">
-                        <div class="text-xs text-muted mb-1">From</div>
-                        <div
-                            id="tx-detail-from"
-                            class="text-xs break-all"
-                        ></div>
-                    </div>
-                    <div class="mb-2">
-                        <div class="text-xs text-muted mb-1">To</div>
-                        <div id="tx-detail-to" class="text-xs break-all"></div>
-                    </div>
                 </div>
 
                 <!-- ── Timing ── -->
@@ -1139,6 +1132,17 @@
                             class="text-xs break-all"
                         ></div>
                     </div>
+                    <div class="mb-2">
+                        <div class="text-xs text-muted mb-1">From</div>
+                        <div
+                            id="tx-detail-from"
+                            class="text-xs break-all"
+                        ></div>
+                    </div>
+                    <div class="mb-2">
+                        <div class="text-xs text-muted mb-1">To</div>
+                        <div id="tx-detail-to" class="text-xs break-all"></div>
+                    </div>
                 </div>
 
                 <!-- ── Decoded details ── -->

src/popup/views/transactionDetail.js

@@ -130,6 +130,19 @@ function render() {
     if (!tx) return;
     $("tx-detail-hash").innerHTML = txHashHtml(tx.hash);
 
+    // Blockie identicon for the transaction hash
+    const blockieEl = $("tx-detail-blockie");
+    if (blockieEl) {
+        blockieEl.innerHTML = "";
+        const img = document.createElement("img");
+        img.src = makeBlockie(tx.hash);
+        img.width = 48;
+        img.height = 48;
+        img.style.imageRendering = "pixelated";
+        img.style.borderRadius = "50%";
+        blockieEl.appendChild(img);
+    }
+
     const fromTitle = addressTitle(tx.from, state.wallets);
     const toTitle = addressTitle(tx.to, state.wallets);
     $("tx-detail-from").innerHTML = txAddressHtml(