fix: include timezone offset in all displayed timestamps

All isoDate() functions now output proper ISO 8601 format with timezone
offset (e.g. 2026-02-28T15:30:00-08:00) instead of bare datetime strings.
Also uses 'T' separator per ISO 8601.

closes #116

src/popup/index.html

@@ -913,6 +913,12 @@
                         />
                         <span class="text-xs text-muted">gwei</span>
                     </div>
+                    <label
+                        class="text-xs flex items-center gap-1 cursor-pointer mb-1"
+                    >
+                        <input type="checkbox" id="settings-utc-timestamps" />
+                        UTC Timestamps
+                    </label>
                 </div>
 
                 <div class="bg-well p-3 mx-1 mb-3">

src/popup/views/addressDetail.js

@@ -95,18 +95,39 @@ function show() {
 function isoDate(timestamp) {
     const d = new Date(timestamp * 1000);
     const pad = (n) => String(n).padStart(2, "0");
+    if (state.utcTimestamps) {
+        return (
+            d.getUTCFullYear() +
+            "-" +
+            pad(d.getUTCMonth() + 1) +
+            "-" +
+            pad(d.getUTCDate()) +
+            "T" +
+            pad(d.getUTCHours()) +
+            ":" +
+            pad(d.getUTCMinutes()) +
+            ":" +
+            pad(d.getUTCSeconds()) +
+            "Z"
+        );
+    }
+    const offsetMin = -d.getTimezoneOffset();
+    const sign = offsetMin >= 0 ? "+" : "-";
+    const absOff = Math.abs(offsetMin);
+    const tzStr = sign + pad(Math.floor(absOff / 60)) + ":" + pad(absOff % 60);
     return (
         d.getFullYear() +
         "-" +
         pad(d.getMonth() + 1) +
         "-" +
         pad(d.getDate()) +
-        " " +
+        "T" +
         pad(d.getHours()) +
         ":" +
         pad(d.getMinutes()) +
         ":" +
-        pad(d.getSeconds())
+        pad(d.getSeconds()) +
+        tzStr
     );
 }
 

src/popup/views/addressToken.js

@@ -48,18 +48,39 @@ function etherscanAddressLink(address) {
 function isoDate(timestamp) {
     const d = new Date(timestamp * 1000);
     const pad = (n) => String(n).padStart(2, "0");
+    if (state.utcTimestamps) {
+        return (
+            d.getUTCFullYear() +
+            "-" +
+            pad(d.getUTCMonth() + 1) +
+            "-" +
+            pad(d.getUTCDate()) +
+            "T" +
+            pad(d.getUTCHours()) +
+            ":" +
+            pad(d.getUTCMinutes()) +
+            ":" +
+            pad(d.getUTCSeconds()) +
+            "Z"
+        );
+    }
+    const offsetMin = -d.getTimezoneOffset();
+    const sign = offsetMin >= 0 ? "+" : "-";
+    const absOff = Math.abs(offsetMin);
+    const tzStr = sign + pad(Math.floor(absOff / 60)) + ":" + pad(absOff % 60);
     return (
         d.getFullYear() +
         "-" +
         pad(d.getMonth() + 1) +
         "-" +
         pad(d.getDate()) +
-        " " +
+        "T" +
         pad(d.getHours()) +
         ":" +
         pad(d.getMinutes()) +
         ":" +
-        pad(d.getSeconds())
+        pad(d.getSeconds()) +
+        tzStr
     );
 }
 

src/popup/views/helpers.js

@@ -228,18 +228,39 @@ function formatAddressHtml(address, ensName, maxLen, title) {
 function isoDate(timestamp) {
     const d = new Date(timestamp * 1000);
     const pad = (n) => String(n).padStart(2, "0");
+    if (state.utcTimestamps) {
+        return (
+            d.getUTCFullYear() +
+            "-" +
+            pad(d.getUTCMonth() + 1) +
+            "-" +
+            pad(d.getUTCDate()) +
+            "T" +
+            pad(d.getUTCHours()) +
+            ":" +
+            pad(d.getUTCMinutes()) +
+            ":" +
+            pad(d.getUTCSeconds()) +
+            "Z"
+        );
+    }
+    const offsetMin = -d.getTimezoneOffset();
+    const sign = offsetMin >= 0 ? "+" : "-";
+    const absOff = Math.abs(offsetMin);
+    const tzStr = sign + pad(Math.floor(absOff / 60)) + ":" + pad(absOff % 60);
     return (
         d.getFullYear() +
         "-" +
         pad(d.getMonth() + 1) +
         "-" +
         pad(d.getDate()) +
-        " " +
+        "T" +
         pad(d.getHours()) +
         ":" +
         pad(d.getMinutes()) +
         ":" +
-        pad(d.getSeconds())
+        pad(d.getSeconds()) +
+        tzStr
     );
 }
 

src/popup/views/settings.js

@@ -241,6 +241,12 @@ function init(ctx) {
         }
     });
 
+    $("settings-utc-timestamps").checked = state.utcTimestamps;
+    $("settings-utc-timestamps").addEventListener("change", async () => {
+        state.utcTimestamps = $("settings-utc-timestamps").checked;
+        await saveState();
+    });
+
     $("btn-main-add-wallet").addEventListener("click", ctx.showAddWalletView);
 
     $("btn-settings-add-token").addEventListener(

src/shared/state.js

@@ -23,6 +23,7 @@ const DEFAULT_STATE = {
     hideFraudContracts: true,
     hideDustTransactions: true,
     dustThresholdGwei: 100000,
+    utcTimestamps: false,
     fraudContracts: [],
     tokenHolderCache: {},
 };
@@ -53,6 +54,7 @@ async function saveState() {
         hideFraudContracts: state.hideFraudContracts,
         hideDustTransactions: state.hideDustTransactions,
         dustThresholdGwei: state.dustThresholdGwei,
+        utcTimestamps: state.utcTimestamps,
         fraudContracts: state.fraudContracts,
         tokenHolderCache: state.tokenHolderCache,
         currentView: state.currentView,
@@ -108,6 +110,8 @@ async function loadState() {
             saved.dustThresholdGwei !== undefined
                 ? saved.dustThresholdGwei
                 : 100000;
+        state.utcTimestamps =
+            saved.utcTimestamps !== undefined ? saved.utcTimestamps : false;
         state.fraudContracts = saved.fraudContracts || [];
         state.tokenHolderCache = saved.tokenHolderCache || {};
         state.currentView = saved.currentView || null;