Add per-task terminals over WebSocket with an xterm.js Terminal tab

web/style.css

@@ -300,6 +300,7 @@ textarea {
 .transcript-view,
 .changes-view,
 .files-view,
+.terminal-view,
 .inbox-view {
   flex: 1;
   min-height: 0;
@@ -1132,6 +1133,33 @@ pre.diff .meta {
   overflow: auto;
 }
 
+.terminal-header {
+  display: flex;
+  align-items: baseline;
+  gap: 12px;
+  padding: 8px 16px;
+  border-bottom: 1px solid var(--border);
+}
+
+.terminal-title {
+  flex: 1;
+  color: var(--muted);
+}
+
+.terminal-status {
+  font-size: 11px;
+  color: var(--muted);
+  white-space: nowrap;
+}
+
+.terminal-screen {
+  flex: 1;
+  min-height: 0;
+  overflow: hidden;
+  padding: 6px 8px;
+  background: var(--bg);
+}
+
 .entries {
   display: flex;
   flex-direction: column;