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/order.ludic

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+# order.ludic - the roll's order and its pages. Forty frames is a pile in taking order; once a frame
+# has a grade the useful question is which are the best. The index is mapped, never the roll resorted.
+export const PHOTO_NEWEST: int = 0
+export const PHOTO_BEST: int = 1
+export const PHOTO_BY_SUBJECT: int = 2
+export const PHOTO_PAGE: int = 8
+
+var pht_sort: int = 0
+var pht_page: int = 0
+var pht_order: []int = null
+
+export function photo_sort() -> int { return pht_sort }
+export function photo_sort_next() -> void { pht_sort = (pht_sort + 1) % 3 }
+export function photo_sort_set(s: int) -> void { pht_sort = Math.clamp(s, 0, 2) }
+
+# the roll in the chosen order: newest first, best first, or by subject
+export function photo_order() -> []int {
+  pht_order = new []int
+  for i in 0 .. pht_n { push(pht_order, i) }
+  if pht_sort == PHOTO_NEWEST {
+    for i in 0 .. pht_n { pht_order[i] = pht_n - 1 - i }
+    return pht_order
+  }
+  for i in 0 .. pht_n {
+    var best = i
+    for k in i + 1 .. pht_n { if pht_before(pht_order[k], pht_order[best]) { best = k } }
+    let t = pht_order[i]
+    pht_order[i] = pht_order[best]
+    pht_order[best] = t
+  }
+  return pht_order
+}
+
+function pht_before(a: int, b: int) -> bool {
+  if pht_sort == PHOTO_BEST { return pht_grade[a] > pht_grade[b] }
+  return pht_mask[a] < pht_mask[b]
+}
+
+export function photo_pages() -> int { return (pht_n + PHOTO_PAGE - 1) / PHOTO_PAGE }
+export function photo_page_now() -> int { return pht_page }
+export function photo_page_step(d: int) -> void { pht_page = Math.clamp(pht_page + d, 0, Math.max(photo_pages() - 1, 0)) }
+
+# a page of the roll, in its order; the page is held inside the roll
+export function photo_page_list() -> []int {
+  let out = new []int
+  if pht_n == 0 { return out }
+  let order = photo_order()
+  if pht_page >= photo_pages() { pht_page = photo_pages() - 1 }
+  for k in 0 .. PHOTO_PAGE {
+    let oi = pht_page * PHOTO_PAGE + k
+    if oi < pht_n { push(out, order[oi]) }
+  }
+  return out
+}