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, 28 insertions, 0 deletions

diff --git a/src/lib/archive.source.sh b/src/lib/archive.source.sh
index b53a782..c27c65c 100644
--- a/src/lib/archive.source.sh
+++ b/src/lib/archive.source.sh
@@ -1,3 +1,31 @@
+# Tarball creation plus the naming helpers that decide what the archive file is
+# called. The naming helpers (tarball_name_plan / generated_tarball_name) were
+# moved here from album-metadata.source.sh (task 6r0): naming the archive is part
+# of this module's tarball concern, alongside tarball() which writes it. The
+# planned-name variant is consumed by the dry-run preview; the generated variant
+# (with a real timestamp slug) is consumed by the album coordinator when it
+# actually creates the archive. Behaviour and signatures are unchanged.
+
+# Print the tarball name as it will appear in the dry-run plan: the incoming
+# directory's basename, a literal "<timestamp>" placeholder, and the suffix.
+tarball_name_plan() {
+    local base
+
+    base=$(basename "$INCOMING_DIR")
+    printf '%s-<timestamp>%s\n' "$base" "$TARBALL_SUFFIX"
+}
+
+# Print the real tarball name used at generation time: the incoming directory's
+# basename, the current timestamp slug, and the configured suffix.
+generated_tarball_name() {
+    local base
+    local timestamp
+
+    base=$(basename "$INCOMING_DIR")
+    timestamp=$(current_timestamp_slug)
+    printf '%s-%s%s\n' "$base" "$timestamp" "$TARBALL_SUFFIX"
+}
+
 tarball() {
     local -r tarball_name="$1"; shift
     local -r tarball_suffix="$TARBALL_SUFFIX"