Add example-name hint to the preset-name keyboard

The preset-name keypad (used both when adding a preset via manual
coordinates and after an address search) only showed "Name
(optional):" with no indication of what kind of name was expected.
Adds a localized hint line with example names (e.g. "Home, Work,
Holiday home") under the title in both runPresetNameKeypad()
(location_presets_screen.cpp) and runNameKeypad()
(address_search_screen.cpp), measuring the header height dynamically
via getCursorY() the same way runAddressKeyboard() already does, so
the input field and keyboard shift down to make room regardless of
translation length.

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

src/i18n_en.h

@@ -228,6 +228,8 @@ static const char* const I18N_EN[] = {
     "Setup Complete",
     "The setup process is now complete. All data has been saved to the SD card in the folder ",
     ". From the next boot, WiFi will connect automatically.",
+
+    "e.g. Home, Work, Holiday home",
 };
 
 static_assert(sizeof(I18N_EN) / sizeof(I18N_EN[0]) == (size_t)StringId::COUNT,