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/slug.ludic

@@ -0,0 +1,31 @@
+# slug.ludic - a frame's tags as a file name: lower case letters and digits, words joined by dashes,
+# at most 24 characters, so a folder of photographs browses well
+const PHT_ALPHA: string = "0123456789abcdefghijklmnopqrstuvwxyz"
+
+export function photo_slug(tags: string) -> string {
+  var out = ""
+  var n = 0
+  var i = 0
+  var last_dash = true
+  while i < len(tags) and n < 24 {
+    var c = tags[i]
+    if c >= 65 and c <= 90 { c = c + 32 }
+    var k = -1
+    if c >= 48 and c <= 57 { k = c - 48 }
+    if c >= 97 and c <= 122 { k = c - 97 + 10 }
+    if k >= 0 {
+      let ch: string = PHT_ALPHA[k..k + 1]
+      out = out + ch
+      last_dash = false
+      n += 1
+    } else if (c == 32 or c == 44) and not last_dash and n > 0 {
+      out = out + "-"
+      last_dash = true
+      n += 1
+    }
+    i += 1
+  }
+  while Text.ends_with(out, "-") { out = Text.slice(out, 0, len(out) - 1) }
+  if len(out) == 0 { return "photo" }
+  return out
+}