rm0 wire stats feature into generate with STATS_PAGE toggle

Final integration of the stats-site feature:

- Add STATS_PAGE config (default yes) mirroring SPLASH_PAGE through every
  layer: shuriken.default.conf, apply_config_defaults, CLI_OPTION_SPEC
  (--stats/--no-stats), the CLI_CONFIG_OVERRIDE_TARGETS allowlist (without
  which the flag was silently ignored), usage text, yes/no validation,
  print_config, the action config list + effective-setting log, the
  generation metadata, and the dry-run plan.
- generate() now calls a gated generate_stats_pages helper after the album
  pages (and before archiving, so the stats/camera pages are tarballed):
  collect_photo_exif_stats + render_stats_page . . + render_camera_pages . .
- Emit "stats_page" in shuriken.json next to "splash_page".
- Gate the header Stats nav link behind STATS_PAGE via a new
  render_stats_page_html config_html field, so it is hidden (no 404) when
  stats are disabled.
- Document STATS_PAGE and --stats/--no-stats in the README.
- Tests: full --generate produces stats.html + camera-<slug>.html + the nav
  link and stats_page=true; --no-stats suppresses all three and sets
  stats_page=false; print-config and metadata expectations updated.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/src/lib/config.validate.source.sh b/src/lib/config.validate.source.sh
index b858144..bd2fccf 100644
--- a/src/lib/config.validate.source.sh
+++ b/src/lib/config.validate.source.sh
@@ -193,6 +193,7 @@ validate_common_config() {
     validate_positive_integer_config_var TAR_TIMEOUT || return
     validate_yes_no_config_var SHUFFLE || return
     validate_yes_no_config_var SPLASH_PAGE || return
+    validate_yes_no_config_var STATS_PAGE || return
     validate_yes_no_config_var TARBALL_INCLUDE || return
 }