Add progress counter and faces-pending sentinel bypass to update.rb

- process_dir() takes idx/total args and prints [N/total] prefix on every
  Scanning/Skipping line so long runs are easy to monitor via tail -f
- faces_pending?() checks album.json for any image with faces: null when
  faces.enabled is true; if found, the sentinel skip is bypassed so those
  images get processed even though the directory mtime hasn't changed
- This handles the case where face detection is newly enabled on a library
  that was previously indexed without it — no --force needed on subsequent
  runs after the initial catch-up

Resume after abort: sentinel is only touched after atomic_write_json, so
an aborted directory reruns cleanly. Already-completed directories skip
normally; partially-detected batches rerun from scratch (safe/idempotent).

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

1 files changed, 18 insertions, 3 deletions

diff --git a/scripts/update.rb b/scripts/update.rb
index 1a00ddf..5671330 100644
--- a/scripts/update.rb
+++ b/scripts/update.rb
@@ -51,15 +51,20 @@ def process_dir(dir, idx, total)
   label  = rel.empty? ? '(root)' : rel
   prefix = "[#{idx}/#{total}]"
 
+  pending_faces = false
   unless FORCE_UPDATE
     sentinel = File.join(dir, SENTINEL_FILE)
     if File.exist?(sentinel) && File.mtime(sentinel) >= File.mtime(dir)
-      puts "#{prefix} Skipping #{label} (unchanged)"
-      return
+      if faces_pending?(dir)
+        pending_faces = true   # fall through, but only to run face detection
+      else
+        puts "#{prefix} Skipping #{label} (unchanged)"
+        return
+      end
     end
   end
 
-  puts "#{prefix} Scanning #{label}"
+  puts "#{prefix} Scanning #{label}#{' (face detection pending)' if pending_faces}"
 
   json_path = File.join(dir, 'album.json')
   data = load_json(json_path)
@@ -290,6 +295,16 @@ rescue JSON::ParserError => e
   {}
 end
 
+def faces_pending?(dir)
+  return false unless FACES_ENABLED
+  json_path = File.join(dir, 'album.json')
+  return false unless File.exist?(json_path)
+  (load_json(json_path)['files'] || {}).any? do |name, meta|
+    IMAGE_EXTS.include?(File.extname(name).downcase.delete_prefix('.')) &&
+      meta['faces'].nil?
+  end
+end
+
 # Fields the admin controls — never overwrite with stale values from our earlier read.
 ADMIN_ALBUM_KEYS = %w[title description cover cover_dynamic sort_reverse visible].freeze
 ADMIN_FILE_KEYS  = %w[title caption visible].freeze