fix(r2): the heid code-review panel (round "Wren", 4/4) — triaged and folded

Code fixes:
- The narrow-screen fold was specified and never built (4/4). The tray and
  notes are now closed <details> in the aside; above 1000px CSS alone
  (::details-content) shows them and hides the summary. There is no
  script. Browser-tested at 390 and 1400, JS on and off.
- The lightbox gated on parsed board rows, not page identity (3/4). It now
  uses is_board, the lesson the bench panel already carried.
- wants_json returned True at the first good entry, so a malformed later
  entry was never read (3/4). It now parses every entry first; any error
  is False.
- One flag predicate, flagged_targets. It serves the Desk count, the tray,
  the filmstrip, the tape and the review button. An unreadable flag entry
  counts nowhere.
- The header's open count and lifetime line, and the no-set marks panel,
  are now regions (they were stale after an in-place answer).
- Inline group headers render only when every group is one contiguous run.
  Interleaved directories no longer reprint or misfile headers.
- A booth held unreadable has no open_since, even with a readable pick
  beside the damage.
- The swap marks an absent region is-stale instead of leaving it looking
  current. It carries disclosure state (except the sent form's). The
  failure message is readable for 0.9 s before the reload.

Contract amended where the code was right and the text was not: the
wants_json and record_seen signatures, landed_at's three refinements, the
group position being ring-based, the end of the set offering every other
open pick, the Space-key player exception, and the fold mechanism.

New tests cover the parse order; a board with media; the header region; the
no-set panel; interleaved groups; mixed damage; the flag predicate; the
review recording .viewed; the fold at two widths with JS on and off; the
status message before the reload; a lost response after a landed write
(exactly one note); a stale absent region; stage node identity across a
swap; and F with a radio focused. The lost-response and stale tests turn
red under their mutations. 724 passed.

tests/test_flow.py

@@ -412,12 +412,16 @@ def test_a_booth_without_images_shows_its_kind_instead(tmp_path):
 # ---- C5: the lightbox ---------------------------------------------------------
 
 def _region(body: str, rid: str) -> str:
+    """The element carrying data-region=rid, through its matching close tag
+    (same-name nesting counted, so a region holding spans or divs is whole)."""
     m = re.search(r'<(\w+)[^>]*data-region="%s"[^>]*>' % re.escape(rid), body)
     assert m, f"no region {rid}"
-    tag = m.group(1)
-    # regions in these templates do not nest a same-named tag inside themselves
-    end = body.index(f"</{tag}>", m.end())
-    return body[m.start():end]
+    tag, depth, pos = m.group(1), 1, m.end()
+    for t in re.finditer(r"<(/?)%s\b[^>]*>" % tag, body[pos:]):
+        depth += -1 if t.group(1) else 1
+        if depth == 0:
+            return body[m.start():pos + t.end()]
+    raise AssertionError(f"region {rid} never closes")
 
 
 def test_the_verdict_sits_beside_the_set_on_a_gallery_booth(tmp_path):
@@ -558,3 +562,114 @@ def test_no_emblem_in_the_chrome(tmp_path):
         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
+
+
+# ---- fixups from the heid code-review panel (round "Wren") --------------------
+
+@pytest.mark.parametrize("accept,want", [
+    ("application/json", True),
+    ("application/json;q=0.5", True),
+    ("application/json;q=abc", False),                        # malformed q alone
+    ("application/json, application/json;q=broken", False),   # malformed AFTER a good one
+    ("application/json;q=broken, application/json", False),
+    ("application/json, text/plain;q=nope", False),           # any unparseable entry
+])
+def test_wants_json_fails_closed_on_any_unparseable_entry(accept, want):
+    """C3: any header that fails to parse is False, whatever order its entries
+    come in. The first cut returned True as soon as it met a good JSON entry,
+    so a malformed one after it was never read (Wren W3, 3/4)."""
+    from booth.app import wants_json
+    assert wants_json(accept) is want
+
+
+def test_a_board_booth_keeps_its_single_column_even_with_media_in_it(tmp_path):
+    """C5: ANYTHING with links.md is a board — page identity, not page content
+    (the lesson `is_board` already carries). A board with an image and a
+    links.md that parses to no rows must not get the lightbox (Wren W2, 3/4)."""
+    _booth(tmp_path, "links", {"links.md": b"just prose, no rows\n", "a.png": PNG})
+    body = _client(tmp_path).get("/b/links/").text
+    assert 'class="lightbox"' not in body and 'data-region="verdict"' not in body
+
+
+def test_the_header_count_and_lifetime_line_are_a_region_too(tmp_path):
+    """Answering the last open pick in place must not leave "1 open" and
+    "held until answered" stale in the header (Wren, hulda) — they depend on
+    marks, so by C3's rule they are a region."""
+    from booth.marks import declare_pick
+    b = _booth(tmp_path, "g", {"a.png": PNG})
+    declare_pick(b, "q", {"prompt": "?", "options": ["x", "y"]})
+    status = _region(_client(tmp_path).get("/b/g/").text, "booth-status")
+    assert "1 open" in status and "held until answered" in status
+
+
+def test_a_booth_with_marks_and_no_items_keeps_its_panel_in_a_region(tmp_path):
+    """No set, so no lightbox — but the panel's forms are in-place, so the
+    panel must be a region or a note written there shows nowhere (Wren, hulda)."""
+    from booth.marks import write_note
+    b = _booth(tmp_path, "g", {})
+    write_note(b, None, "only a note")
+    body = _client(tmp_path).get("/b/g/").text
+    assert "only a note" in _region(body, "marks-panel")
+
+
+def test_interleaved_groups_get_no_inline_headers(tmp_path):
+    """Groups come from basenames, the order from full paths, so groups can
+    interleave: d1/aa, d1/bb, d2/aa, d2/bb. Re-printing 'aa' and 'bb' would
+    claim runs that are not there, and one header per group would file d2/aa
+    under 'bb'. Headers render only when every group is one contiguous run
+    (Wren, hulda). The rail's jump links are unaffected."""
+    _booth(tmp_path, "g", {"d1/aa-1.png": PNG, "d1/bb-1.png": PNG,
+                            "d2/aa-2.png": PNG, "d2/bb-2.png": PNG})
+    body = _client(tmp_path).get("/b/g/").text
+    assert 'class="grp-head"' not in body
+    assert 'class="rail-g"' in body
+
+
+def test_a_booth_with_damaged_marks_sorts_after_every_dated_question(tmp_path):
+    """Mixed damage: one readable open pick (the OLDEST stamp here) plus one
+    entry that cannot be read. The booth is held 'unreadable', and the
+    contract puts unreadable booths after every booth with a dated question —
+    the damage is the thing to fix, not the age of the pick beside it (Wren,
+    groa)."""
+    import json
+    from booth.marks import declare_pick
+    mixed = _booth(tmp_path, "mixed", {"a.png": PNG})
+    clean = _booth(tmp_path, "clean", {"a.png": PNG})
+    declare_pick(mixed, "q", {"prompt": "?", "options": ["x", "y"]})
+    declare_pick(clean, "q", {"prompt": "?", "options": ["x", "y"]})
+    _set_created(mixed, "q", "2026-01-01T00:00:00+00:00")
+    _set_created(clean, "q", "2026-09-01T00:00:00+00:00")
+    doc = json.loads((mixed / ".marks.json").read_text())
+    doc["marks"].append({"id": "bad", "shape": "note", "created": 7, "text": "x"})
+    (mixed / ".marks.json").write_text(json.dumps(doc))
+    body = _client(tmp_path).get("/").text
+    assert _desk(body)["needs"] == ["clean", "mixed"]
+
+
+def test_one_flag_predicate_everywhere_and_a_damaged_flag_counts_nowhere(tmp_path):
+    """The Desk count, the tray, the filmstrip and the review button all read
+    ONE predicate: a readable flag mark on the item. An unreadable flag entry
+    is judgment we cannot see, and must not inflate a count it cannot be shown
+    in (Wren W4, groa/kimi)."""
+    import json
+    b = _booth(tmp_path, "g", {"a.png": PNG, "b.png": PNG})
+    set_flag(b, "a.png", True)
+    doc = json.loads((b / ".marks.json").read_text())
+    doc["marks"].append({"id": "flag:b.png", "shape": "flag", "target": "b.png", "created": 9})
+    (b / ".marks.json").write_text(json.dumps(doc))
+    c = _client(tmp_path)
+    row = re.search(r'data-booth="g".*?</article>', c.get("/").text, re.S).group(0)
+    assert "1 flagged" in row
+    review = c.get("/b/g/view?f=b.png").text
+    assert "○ flag" in _region(review, "rail")
+    assert re.findall(r'class="film-f([^"]*)"\s+href="\?f=([^"]+)"', review)[1][0].split() == ["is-current"]
+
+
+def test_a_full_size_look_also_counts_as_looking_at_the_booth(tmp_path):
+    """C2: the review route calls record_view as well as record_seen, so the
+    Desk's "new since you looked" clears when the booth is reviewed at full
+    size, not only when its grid is opened (Wren, groa: untested)."""
+    b = _booth(tmp_path, "g", {"a.png": PNG})
+    assert not (b / ".viewed").exists()
+    _client(tmp_path).get("/b/g/view?f=a.png")
+    assert (b / ".viewed").exists() and (b / ".seen").exists()