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.

tests/test_flow.py

@@ -476,3 +476,85 @@ def test_every_mark_dependent_element_is_a_swappable_region(tmp_path):
     _booth(tmp_path, "links", {"links.md": b"- [x](http://x/) <sub>\xc2\xb7 a \xc2\xb7 2026-09-01 10:00</sub>\n"})
     board = _client(tmp_path).get("/b/links/").text
     assert 'data-region="verdict"' not in board and 'class="lightbox"' not in board
+
+
+# ---- C6: the review -----------------------------------------------------------
+
+def test_an_audio_item_is_reviewed_like_a_picture(tmp_path):
+    """The tracer for C6. A track gets the review page — its native player on
+    the stage, no Fit/1:1 toggle (that is for images only), and the judgment
+    rail with a flag that lands back here."""
+    _booth(tmp_path, "g", {"a.png": PNG, "b.mp3": b"ID3", "c.mp3": b"ID3"})
+    r = _client(tmp_path).get("/b/g/view?f=b.mp3", follow_redirects=False)
+    assert r.status_code == 200
+    body = r.text
+    stage = body[body.index('id="vstage"'):]
+    assert len(re.findall(r"<audio\b[^>]*\bcontrols\b", stage.split("</div>")[0])) == 1
+    assert 'id="vtoggle"' not in body and ">1:1<" not in body
+    rail = _region(body, "rail")
+    assert 'name="back" value="view"' in rail and 'name="f" value="b.mp3"' in rail
+    assert "2 of 3" in rail and "#2" in rail
+
+
+def test_filmstrip_and_tape_are_the_review_ring_with_seen_and_flags(tmp_path):
+    """One list, three surfaces: the filmstrip and the tape are the ring in
+    set order. The tape counts seen ∩ ring — including the item being looked
+    at, which is recorded before the page renders; a doc is never in it."""
+    b = _booth(tmp_path, "g", {"a.png": PNG, "b.md": b"# b", "c.png": PNG, "d.mp3": b"ID3"})
+    set_flag(b, "d.mp3", True)
+    c = _client(tmp_path)
+    c.get("/b/g/view?f=a.png")
+    body = c.get("/b/g/view?f=c.png").text
+    film = re.findall(r'<a class="film-f([^"]*)"\s+href="\?f=([^"]+)"', _region(body, "film"))
+    assert [(rel, cls.split()) for cls, rel in film] == [
+        ("a.png", []), ("c.png", ["is-current"]), ("d.mp3", ["is-flagged"])]
+    assert re.findall(r'class="film-ord">#(\d)<', body) == ["1", "3", "4"]   # whole-set numbers
+    tape = _region(body, "tape")
+    assert re.findall(r'<a class="tape-s([^"]*)"', tape) == [" is-seen", " is-current", " is-flagged"]
+    assert "2 of 3 seen" in tape
+
+
+def test_a_question_about_this_item_is_answerable_here_and_the_rest_wait_for_the_end(tmp_path):
+    """The rail offers a pick TARGETING the item; booth-level picks are a count
+    and a link — until the last item, where the end of the set offers them
+    all, each landing back on the review."""
+    from booth.marks import declare_pick
+    b = _booth(tmp_path, "g", {"a.png": PNG, "b.png": PNG})
+    declare_pick(b, "about-a", {"prompt": "Is a sharp?", "options": ["yes", "no"]}, target="a.png")
+    declare_pick(b, "overall", {"prompt": "Ship the set?", "options": ["yes", "no"]})
+    c = _client(tmp_path)
+    first = _region(c.get("/b/g/view?f=a.png").text, "rail")
+    assert "Is a sharp?" in first and "Ship the set?" not in first
+    assert "1 more open question on this booth" in first
+    assert first.count('name="back" value="view"') >= 2          # flag + the pick
+    last = _region(c.get("/b/g/view?f=b.png").text, "rail")
+    assert "End of the set" in last
+    assert "Ship the set?" in last and "Is a sharp?" in last
+    form = re.search(r'<form class="mark-form"[^>]*>.*?Ship the set\?|Ship the set\?.*?</form>', last, re.S)
+    assert form and 'name="f" value="b.png"' in last
+
+
+def test_only_a_picture_gets_the_fit_toggle_and_blur_stays_honest(tmp_path):
+    from booth.app import set_blurred
+    b = _booth(tmp_path, "g", {"a.png": PNG, "v.webm": b"\x1aE"})
+    set_blurred(b, "a.png", True)
+    c = _client(tmp_path)
+    pic = c.get("/b/g/view?f=a.png").text
+    assert 'id="vtoggle"' in pic and ">Fit<" in pic and ">1:1<" in pic
+    assert 'class="vstage fit is-blurred"' in pic and "blur is cosmetic" in pic
+    vid = c.get("/b/g/view?f=v.webm").text
+    assert 'id="vtoggle"' not in vid and re.search(r"<video\b[^>]*\bcontrols\b", vid)
+
+
+# ---- C7: copy and brand -------------------------------------------------------
+
+def test_no_emblem_in_the_chrome(tmp_path):
+    """Ruling `emblem=no`: the top bar carries the brand dot and the name, and
+    no image at all."""
+    _booth(tmp_path, "g", {"a.png": PNG})
+    c = _client(tmp_path)
+    for path in ("/", "/b/g/", "/b/g/view?f=a.png"):
+        body = c.get(path).text
+        m = re.search(r'<header class="topbar">.*?</header>', body, re.S)
+        if m:
+            assert "<img" not in m.group(0) and "<svg" not in m.group(0), path