show email alongside CN in TUI main menu cert list

CertInfo.email was already populated from index.txt but never
rendered; add it as a fixed-width column next to CN in the cert
list rows (blank when unknown).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

openvpncertupdate.py

@@ -938,7 +938,7 @@ def show_main_screen(
                 cert = certs[i]
                 box  = "[X]" if cert.cn in checked else "[ ]"
                 lbl  = _expiry_label(cert)
-                line = f"  {box} {lbl:<18} {cert.cn}"
+                line = f"  {box} {lbl:<18} {cert.cn:<20} {cert.email}"
                 try:
                     stdscr.addstr(row_y, 0, line.ljust(sw - 1)[:sw - 1], sel_attr)
                 except curses.error:

tests/test_main_screen.py

@@ -28,12 +28,13 @@ from openvpncertupdate import (
 # Helpers
 # ---------------------------------------------------------------------------
 
-def _cert(cn: str, days_left: int) -> CertInfo:
+def _cert(cn: str, days_left: int, email: str = "") -> CertInfo:
     """Build a minimal CertInfo; expires value is a plausible UTC datetime."""
     return CertInfo(
         cn=cn,
         expires=datetime(2030, 1, 1, tzinfo=timezone.utc),
         days_left=days_left,
+        email=email,
     )
 
 
@@ -121,6 +122,28 @@ def test_cursor_row_has_reverse_attribute():
     assert alice_calls and not (alice_calls[0].args[3] & _curses.A_REVERSE)
 
 
+def test_cert_row_shows_email():
+    certs = [_cert("alice", 10, email="alice@example.com"), _cert("bob", 3)]
+    stdscr = _make_stdscr()
+    stdscr.getch.side_effect = [ord("q")]
+    with patch("openvpncertupdate.init_colors"):
+        show_main_screen(stdscr, certs)
+    alice_calls = [c for c in stdscr.addstr.call_args_list if "alice" in str(c.args[2])]
+    assert alice_calls
+    assert "alice@example.com" in alice_calls[0].args[2]
+
+
+def test_cert_row_blank_when_no_email():
+    certs = [_cert("bob", 3)]  # email defaults to ""
+    stdscr = _make_stdscr()
+    stdscr.getch.side_effect = [ord("q")]
+    with patch("openvpncertupdate.init_colors"):
+        show_main_screen(stdscr, certs)
+    bob_calls = [c for c in stdscr.addstr.call_args_list if "bob" in str(c.args[2])]
+    assert bob_calls
+    assert "(none)" not in bob_calls[0].args[2]
+
+
 # ---------------------------------------------------------------------------
 # Enter on cert → RENEW_SELECTED
 # ---------------------------------------------------------------------------