fix: show cursor in Certificate Details form

Two bugs combined to make the cursor invisible:
- curses.curs_set(0) was set globally in _main() and never re-enabled
  for the form, so the cursor was hidden the whole time.
- InputField.draw() called win.move() to position the cursor, but all
  fields were drawn in order, so the cursor always landed on the last
  field (password) regardless of which field had focus.

Fix: split draw() into draw() (render only) + place_cursor() (move
only). show_cert_form() now calls curses.curs_set(1) on entry,
place_cursor() on the focused field after drawing all fields, and
curses.curs_set(0) before each return.

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

openvpncertupdate.py

@@ -477,6 +477,12 @@ class InputField:
         try:
             self._win.addstr(self._y, self._x, visible,
                              curses.color_pair(COLOR_NORMAL) | curses.A_UNDERLINE)
+        except curses.error:
+            pass
+
+    def place_cursor(self) -> None:
+        start = max(0, self._cur - self._width + 1)
+        try:
             self._win.move(self._y, self._x + min(self._cur - start, self._width - 1))
         except curses.error:
             pass
@@ -588,6 +594,7 @@ def show_cert_form(
             confirmed=True,
         )
 
+    curses.curs_set(1)
     while True:
         win.clear()
         draw_box(win, "Certificate Details")
@@ -609,6 +616,7 @@ def show_cert_form(
             else:
                 fields[name].draw()
 
+        fields[active[focus]].place_cursor()
         hint = "Tab=next  F5=regen password  Ctrl-S=confirm  Esc=cancel"
         try:
             win.addstr(h - 2, 2, hint[:w - 4], curses.color_pair(COLOR_DISABLED))
@@ -619,8 +627,10 @@ def show_cert_form(
         key = win.getch()
 
         if key == 27:
+            curses.curs_set(0)
             return CertFormResult(cn=cn, email="", password="", confirmed=False)
         if key == 0x13:       # Ctrl-S: immediate submit
+            curses.curs_set(0)
             return _submit()
         if key == 9:          # Tab
             focus = (focus + 1) % len(active)
@@ -644,6 +654,7 @@ def show_cert_form(
             if focus < len(active) - 1:
                 focus += 1
                 continue
+            curses.curs_set(0)
             return _submit()
         fields[active[focus]].handle_key(key)