fix(terminal): position shell dropdown above chevron button

Author: abose

src/styles/Extn-Terminal.less

@@ -298,11 +298,11 @@
     display: inline;
 }
 
-/* ─── Shell dropdown (pops left of flyout actions) ─── */
+/* ─── Shell dropdown (pops above the actions row) ─── */
 .terminal-shell-dropdown {
     position: absolute;
-    bottom: 0;
-    right: 100%;
+    bottom: 100%;
+    right: 0;
     min-width: 180px;
     background: var(--terminal-tab-bg);
     border: 1px solid var(--terminal-border);