feat(terminal): support native terminal cursor rendering

doc/pages/options.asciidoc

@@ -385,6 +385,10 @@ are exclusively available to built-in options.
             set the maximum allowable width of an info box. set to zero for
             no limit.
 
+        *terminal_cursor_native*:::
+            if *yes* or *true*, use native terminal cursor visibility control
+            instead of Kakoune's cursor management (defaults to *false*)
+
 [[startup-info]]
 *startup_info_version* `int`::
     _default_ 0 +

src/main.cc

@@ -604,6 +604,7 @@ void register_options()
                        "    terminal_shift_function_key    int\n"
                        "    terminal_padding_char          codepoint\n"
                        "    terminal_padding_fill          bool\n"
+                       "    terminal_cursor_native         bool\n"
                        "    terminal_info_max_width        int\n",
                        UserInterface::Options{});
     reg.declare_option("modelinefmt", "format string used to generate the modeline",

src/terminal_ui.cc

@@ -1574,6 +1574,13 @@ void TerminalUI::set_ui_options(const Options& options)
 
     m_padding_char = find("terminal_padding_char").map([](StringView s) { return s.column_length() < 1 ? ' ' : s[0_char]; }).value_or(Codepoint{'~'});
     m_padding_fill = find("terminal_padding_fill").map(to_bool).value_or(false);
+
+    bool new_cursor_native = find("terminal_cursor_native").map(to_bool).value_or(false);
+    if (new_cursor_native != m_cursor_native)
+    {
+        m_cursor_native = new_cursor_native;
+        write(STDOUT_FILENO, m_cursor_native ? "\033[?25h" : "\033[?25l");
+    }
 
     m_info_max_width = find("terminal_info_max_width").map(str_to_int_ifp).value_or(0);
 }

src/terminal_ui.hh

@@ -167,6 +167,7 @@ private:
 
     Codepoint m_padding_char = '~';
     bool m_padding_fill = false;
+    bool m_cursor_native = false;
 
     bool m_dirty = false;