feat(r2): C6 the review, and C7

- The zoom route becomes the review for image, video AND audio: the native
  player on the stage for sound and video, the Fit/1:1 toggle for pictures
  only. The judgment rail, the tape and the filmstrip are each a data-region.
  The stage never is, so a playing track survives an in-place save.
- The rail shows the whole-set number, K of M in the review ring and the
  position in the group; then the caption, and the flag and notes, landing
  back here (back=view). A pick targeting this item is answerable in place.
  On the last item the end-of-set block lists what was seen, the flags, and
  every other open question.
- The keys are ← → Space F N Esc. Every one is ignored in an editable field,
  and Esc returns to the grid at the tile you were on.
- _marks.html gains picks_only/back_view, so a pick form has one renderer
  wherever it sits.
- In-place swaps now carry an unsaved draft across. A half-typed note
  survives a flag, except in the form that was just sent.
- The filmstrip keeps the current frame in view.
- C7: no emblem in the chrome, pinned.

Browser tests cover: F typed into the note stays a letter and does not
flag; F outside the note flags in place and the draft survives; Space
moves; Esc lands on the grid tile. 706 passed.

booth/app.py

@@ -1706,19 +1706,56 @@ def create_app(
             "flagged": any(m.shape == "flag" for m in item_marks),
         }
 
-        if item is not None and item.kind == "image":
-            # prev/next ring (wraps; only when there is more than one item in
-            # it). R2 C2: the ring is `review_chain` — the item order filtered to
-            # MEDIA — so a set that mixes pictures and sound steps through both.
-            names = review_chain(items)
+        if item is not None and item.kind in REVIEW_KINDS:
+            # THE REVIEW (R2 C6): images, video and audio at full size with the
+            # judgment on screen. The ring is `review_chain` — the item order
+            # filtered to MEDIA — and the prev/next, the filmstrip and the tape
+            # all read that ONE list, so they cannot disagree about "next".
+            ring = review_chain(items)
+            by_rel = {it.rel: it for it in items}
+            pos = ring.index(f)
             prev_url = next_url = None
-            if f in names and len(names) > 1:
-                i = names.index(f)
-                prev_url = quote(names[(i - 1) % len(names)], safe="/")
-                next_url = quote(names[(i + 1) % len(names)], safe="/")
+            if len(ring) > 1:
+                prev_url = quote(ring[(pos - 1) % len(ring)], safe="/")
+                next_url = quote(ring[(pos + 1) % len(ring)], safe="/")
+            flagged_rels = {m.target for m in marks
+                            if m.shape == "flag" and m.error is None}
+            # recorded above, before this read: the current item counts as seen
+            seen = read_seen(booth) & set(ring)
+            film = [{"name": r, "url": by_rel[r].url, "ordinal": by_rel[r].ordinal,
+                     "kind": by_rel[r].kind, "blurred": by_rel[r].blurred,
+                     "flagged": r in flagged_rels, "seen": r in seen,
+                     "current": r == f} for r in ring]
+            # Position within the group, only when there IS grouping: two or
+            # more groups among the ring. One group for everything says nothing.
+            group = None
+            ring_groups = {by_rel[r].group for r in ring if by_rel[r].group}
+            if item.group and len(ring_groups) > 1:
+                members = [r for r in ring if by_rel[r].group == item.group]
+                group = {"key": item.group, "k": members.index(f) + 1, "n": len(members)}
+            open_now = open_marks(marks)
             return templates.TemplateResponse(
-                request, "view.html", {**common, "prev_url": prev_url, "next_url": next_url}
-            )
+                request, "view.html", {
+                    **common,
+                    "kind": item.kind,
+                    "ordinal": item.ordinal,
+                    "ord_width": len(str(len(items))),
+                    "ring_k": pos + 1,
+                    "ring_m": len(ring),
+                    "prev_url": prev_url,
+                    "next_url": next_url,
+                    "film": film,
+                    "seen_n": len(seen),
+                    "group": group,
+                    # a question ABOUT this item is answerable here; the rest are
+                    # a count and a link — until the last item, where the end of
+                    # the set offers them all
+                    "item_picks": [m for m in open_now if m.target == f],
+                    "other_picks": [m for m in open_now if m.target != f],
+                    "is_last": pos == len(ring) - 1,
+                    "tray": [x for x in film if x["flagged"]],
+                    "back_url": f"/b/{quote(name, safe='')}/#item-{item.url}",
+                })
 
         # .md renders, .txt/.log show as text — viewable in-booth, no download
         if item is not None: