Split album-metadata.source.sh into focused modules (6r0)

album-metadata.source.sh aggregated six unrelated concerns. Move each
along its existing seam (pure mechanical move, no logic changes):

- EXIF presentation (photo_exif_details_html, tooltip helpers, the
  _photo_exif_values_to wrapper) stays in album-metadata.source.sh,
  which is now EXIF-presentation only.
- File counting (count_files, count_incoming_images, count_tree_files)
  -> image.source.sh, which already owns incoming_image_files;
  count_incoming_images is a direct wrapper of it.
- Tarball naming (tarball_name_plan, generated_tarball_name) ->
  archive.source.sh, which already owns tarball()/resolve_tar_opts.
- Generation metadata + JSON (_collect_generation_metadata,
  _generation_metadata_json, write_generation_metadata) -> new
  generation-metadata.source.sh.
- Dry-run (dry_run, collect_dry_run_*, print_dry_run_plan) -> new
  dry-run.source.sh.
- clear_exif_cache -> metadata-cache.source.sh, next to the cache
  primitive cached_photo_identify_output.

LIB_SOURCES (Justfile + src/shuriken.sh): insert generation-metadata
and dry-run right after album-metadata, before album-render/album.
They depend on image, archive, template and metadata-cache (all earlier
or runtime-only calls), and are consumed by the album coordinator and
the dry-run CLI action, which come later. bin/shuriken regenerated via
just build. File-header comments updated to reflect the new homes.

just test, just shellcheck, just check-generated and git diff --check
all pass.

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

1 files changed, 13 insertions, 0 deletions

diff --git a/src/lib/metadata-cache.source.sh b/src/lib/metadata-cache.source.sh
index ba40ca9..7c6d2e3 100644
--- a/src/lib/metadata-cache.source.sh
+++ b/src/lib/metadata-cache.source.sh
@@ -140,3 +140,16 @@ photo_exif_values_to() {
         fi
     done
 }
+
+# Empty the volatile EXIF cache (./cache/exif, parallel to ./dist) so a --force
+# run re-runs `identify` from scratch. Done once up front; the cache then
+# repopulates and is reused for the rest of the run (one identify per photo).
+# Moved here from album-metadata.source.sh (task 6r0): clearing the cache is the
+# lifecycle counterpart of cached_photo_identify_output above, so the cache's
+# creation and destruction now live in the same module.
+clear_exif_cache() {
+    local -r cache_dir="$(dirname "$DIST_DIR")/cache/exif"
+
+    log_verbose "Force generation; clearing EXIF cache $cache_dir"
+    rm -rf "$cache_dir"
+}