Replace GIF flag scan with static ISO alpha-3 country list and SVG flags

- Add countries_inc.php: 252 countries as alpha-3 → name + alpha-3 → alpha-2
  map for flag image lookup; derived from webtrees CountryService, no runtime
  webtrees dependency
- Add 243 Marble SVG flags (xx.svg) plus eng/sct/wls/nir for constituent countries
- Remove 244 full-name GIF flags
- RoleUser: set users_country_code (alpha-3), flag (alpha-2 lowercase), and
  users_country (display name) at load time
- preferences.php, register.php, hauth_register.php: replace opendir GIF scan
  with require_once countries_inc.php
- Templates: replace {section loop=$flags} with {foreach $countries as $code => $name};
  iexplain now uses display name instead of raw flag code

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

1 files changed, 0 insertions, 0 deletions

diff --git a/icons/flags/Cook_Islands.gif b/icons/flags/Cook_Islands.gif
deleted file mode 100755
index 2edb739..0000000
--- a/icons/flags/Cook_Islands.gif
+++ /dev/null