Make coinos the default Electrum server instead of a separate mode

The data-source picker is now just Electrum vs Block explorer; coinos is the
first/default entry in the Electrum server list (our own Fulcrum), with public
servers as failover. Drops the standalone 'coinos' mode and the retired watcher
shim. Old 'coinos' selections migrate to electrum.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

1 files changed, 5 insertions, 13 deletions

diff --git a/src/app.js b/src/app.js
index 81f952c..9cf974e 100644
--- a/src/app.js
+++ b/src/app.js
@@ -1603,15 +1603,11 @@ function explorerCard() {
   const cfg = getExplorerConfig();
   const ecfg = getElectrumServerConfig();
   const setMode = (m) => {
-    const prev = getDataMode();
-    if (m === prev) return;
+    if (m === getDataMode()) return;
     setDataMode(m);
     render();
-    if (wallet.offline) return;
-    // coinos⇄explorer only flips the watcher (same REST data); to/from electrum
-    // swaps the whole backend, so rebuild + rescan there.
-    if ((m === 'electrum') !== (prev === 'electrum')) wallet.reloadExplorer();
-    else wallet.startRealtime();
+    // electrum⇄explorer swaps the whole backend, so rebuild + rescan.
+    if (!wallet.offline) wallet.reloadExplorer();
   };
   return h(
     'div',
@@ -1619,13 +1615,9 @@ function explorerCard() {
     h('h3', {}, t('dataSource')),
     h('p', { class: 'small muted', style: 'margin:0' }, t('dataSourceDesc')),
     h('select', { onChange: (e) => setMode(e.target.value) },
-      h('option', { value: 'coinos', selected: mode === 'coinos' }, t('modeCoinos')),
-      h('option', { value: 'explorer', selected: mode === 'explorer' }, t('modeExplorer')),
-      h('option', { value: 'electrum', selected: mode === 'electrum' }, t('modeElectrum'))
+      h('option', { value: 'electrum', selected: mode === 'electrum' }, t('modeElectrum')),
+      h('option', { value: 'explorer', selected: mode === 'explorer' }, t('modeExplorer'))
     ),
-    mode === 'coinos'
-      ? h('div', { class: 'small faint' }, t('modeCoinosDesc'))
-      : null,
     mode === 'electrum'
       ? h('div', { class: 'col', style: 'gap:8px' },
           h('div', { class: 'small faint' }, t('backendElectrumDesc')),