feat(packages): ludic.photo - a camera's photographs: what the lens sees (the frustum and a line of sight over the ground and the trunks), a grade out of a hundred on size, framing, light and the moment weighted by how much subject there is, the frame's best subject and its tags, the roll with its order and pages, a buyer's price on the grade's curve, the best of each subject; the lens, the light and the market through ports; kept, full, deleted and sold as facts; the roll in its own save section

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packages/ludic.photo/keep.ludic

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+# keep.ludic - the frame onto the roll, and a frame off it
+# The composed frame, kept as `file` on `day` at `hour`: the index, or -1 when the card is full.
+# Every subject in it counts as photographed, and its best grade may rise.
+export function photo_keep(file: string, day: int, hour: float) -> int {
+  if pht_n >= pht_max {
+    pht_fact(PHOTO_FULL, -1)
+    return -1
+  }
+  var firsts = 0
+  for sp in 0 .. 32 { if (pht_pending_mask & (1 << sp)) != 0 and pht_best[sp] == 0 { firsts = firsts | (1 << sp) } }
+  let i = photo_add(day, hour, pht_pending_mask, pht_pending_legend, false, pht_pending_tags, file, pht_pending_grade, pht_pending_why)
+  pht_legend_shot = pht_legend_shot | pht_pending_legend
+  let f = pht_fact(PHOTO_KEPT, i)
+  f.mask = pht_pending_mask
+  f.legend = pht_pending_legend
+  f.firsts = firsts
+  f.grade = pht_pending_grade
+  f.sign = pht_pending_sign
+  f.stars = pht_pending_stars
+  f.file = file
+  f.tags = pht_pending_tags
+  return i
+}
+
+# a frame onto the roll as it stands (a save, an older trip): the index, or -1 when full
+export function photo_add(day: int, hour: float, mask: int, legend: int, sold: bool, tags: string, file: string, grade: int, why: int) -> int {
+  if pht_day == null { pht_blank() }
+  if pht_n >= pht_max { return -1 }
+  let i = pht_n
+  pht_day[i] = day
+  pht_hour[i] = hour
+  pht_mask[i] = mask
+  pht_legend[i] = legend
+  pht_sold[i] = 0
+  if sold { pht_sold[i] = 1 }
+  pht_grade[i] = grade
+  pht_why[i] = why
+  push(pht_tags, tags)
+  push(pht_file, file)
+  pht_n += 1
+  pht_species_shot = pht_species_shot | mask
+  for sp in 0 .. 32 { if (mask & (1 << sp)) != 0 and grade > pht_best[sp] { pht_best[sp] = grade } }
+  return i
+}
+
+# forgetting one: the record goes, the ones after it close up, and the game is told the file
+export function photo_remove(i: int) -> void {
+  if i < 0 or i >= pht_n { return }
+  let f = pht_fact(PHOTO_DELETED, i)
+  f.file = pht_file[i]
+  let tags = new []string
+  let files = new []string
+  for k in 0 .. pht_n {
+    if k == i { continue }
+    push(tags, pht_tags[k])
+    push(files, pht_file[k])
+  }
+  for k in i .. pht_n - 1 {
+    pht_day[k] = pht_day[k + 1]
+    pht_hour[k] = pht_hour[k + 1]
+    pht_mask[k] = pht_mask[k + 1]
+    pht_legend[k] = pht_legend[k + 1]
+    pht_sold[k] = pht_sold[k + 1]
+    pht_grade[k] = pht_grade[k + 1]
+    pht_why[k] = pht_why[k + 1]
+  }
+  pht_tags = tags
+  pht_file = files
+  pht_n -= 1
+  if pht_cover == i { pht_cover = -1 } else if pht_cover > i { pht_cover -= 1 }
+}
+
+export function photo_cover_set(i: int) -> void { pht_cover = i }
+
+# what has been photographed outright (a network's word, a staged trip)
+export function photo_record_set(species: int, legends: int) -> void {
+  pht_species_shot = species
+  pht_legend_shot = legends
+}
+
+export function photo_best_set(sp: int, grade: int) -> void { if sp >= 0 and sp < 32 { pht_best[sp] = grade } }