Add Ctrl+A X to close current session without quitting

session_close() disconnects, closes log, switches to another active
session, then frees the slot. If it's the last session open, exits
the program (same behavior as Q). Menu updated to show X - Close Session.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

termtcp.c

@@ -241,6 +241,7 @@ static void session_switch(int n);
 static void session_next(void);
 static void session_prev(void);
 static void session_new(void);
+static void session_close(void);
 static void do_connect(int idx);
 
 /* ═══════════════════════════════════════════════════════════
@@ -2688,6 +2689,22 @@ static void session_new(void)
     do_connect(idx);
 }
 
+static void session_close(void)
+{
+    if (session_count() <= 1) {
+        if (S->connected) tcp_disconnect();
+        if (S->logging)   close_log();
+        endwin();
+        exit(0);
+    }
+    int idx = session_index();
+    if (S->connected) tcp_disconnect();
+    if (S->logging)   close_log();
+    session_next();          /* S now points to another active session */
+    sessions[idx].active = 0;
+    draw_status();
+}
+
 /* ═══════════════════════════════════════════════════════════
  * Connect helper
  * ═══════════════════════════════════════════════════════════ */
@@ -2829,13 +2846,14 @@ static void ctrl_a_menu(void)
     mvwprintw(w, 2, 4, "C - Connect");
     mvwprintw(w, 3, 4, "D - Disconnect");
     mvwprintw(w, 4, 4, "N - New Session");
-    mvwprintw(w, 5, 4, "1-4 Switch Session");
-    mvwprintw(w, 6, 4, "O - Config / Host Editor");
-    mvwprintw(w, 7, 4, "M - Monitor Options");
-    mvwprintw(w, 8, 4, "L - Toggle Log");
-    mvwprintw(w, 9, 4, "F - Forms & Check-Ins");
-    mvwprintw(w, 10, 4, "H - Help");
-    mvwprintw(w, 11, 4, "Q - Quit");
+    mvwprintw(w, 5, 4, "X - Close Session");
+    mvwprintw(w, 6, 4, "1-4 Switch Session");
+    mvwprintw(w, 7, 4, "O - Config / Host Editor");
+    mvwprintw(w, 8, 4, "M - Monitor Options");
+    mvwprintw(w, 9, 4, "L - Toggle Log");
+    mvwprintw(w, 10, 4, "F - Forms & Check-Ins");
+    mvwprintw(w, 11, 4, "H - Help");
+    mvwprintw(w, 12, 4, "Q - Quit");
     mvwprintw(w, mh-2, 4, "Esc = close");
     wrefresh(w);
 
@@ -2895,6 +2913,10 @@ static void ctrl_a_menu(void)
         session_new();
         break;
 
+    case 'x':
+        session_close();
+        break;
+
     case '1': case '2': case '3': case '4':
         session_switch(ch - '1');
         break;