fix(blur): the heid code-review and bug-hunt panels on r2b merge 1, folded

Both panels ran 4/4 on 5ded5ff. They converged on the board and doc-page
gaps independently.

- A board holding files lost both blur controls (they sat inside the
  board suppression meant for the one-click wipe), while its items'
  "◉ booth" labels pointed at them. Only the wipe is board-suppressed now.
- A blurred doc's own full page rendered clear. Its body is blurred there
  too, with its own reveal and a Reveal all to put the blur back.
- set_booth_blurred followed a planted .blurbooth symlink (`touch`), and
  the new control made that a click away. Anything at the name already
  reads as fogged; otherwise it is created O_CREAT|O_EXCL|O_NOFOLLOW.
- The fog landing echoed `back` unchecked into the 303. It is now built
  from the review ring, as the mark routes do.
- The fog form is its own region, so an in-place save refreshes its
  label. Reveal all stays outside every region: its state lives in the
  tab.
- The review's Space-to-advance no longer swallows Space on a focused
  button or link.
- Top-bar controls stay on one line at phone width.
- Tests tightened:
  - method="post" on the fog forms;
  - exact blur values;
  - a storage READ that throws;
  - an item's own reveal carried across a swap;
  - reveal gated where it can act.

r2b.toml: 26/26 proved. 774 passed.

tests/mutations/r2b.toml

@@ -69,9 +69,9 @@ label = "D2 the control shows without JS (server markup not hidden)"
 file = "booth/templates/booth.html"
 test = "tests/test_flow_browser.py::test_reveal_all_never_shows_without_js_and_a_storage_failure_still_applies_the_click"
 old = '''
-  {% if all_items | selectattr('blurred') | list %}<button type="button" class="reveal-all-btn" data-reveal-all hidden>'''
+  {% if all_items | selectattr('blurred') | list %}<button type="button" class="reveal-all-btn" data-reveal-all hidden title='''
 new = '''
-  {% if all_items | selectattr('blurred') | list %}<button type="button" class="reveal-all-btn" data-reveal-all>'''
+  {% if all_items | selectattr('blurred') | list %}<button type="button" class="reveal-all-btn" data-reveal-all title='''
 
 [[mutation]]
 label = "D2 the control is markup even when nothing is blurred"
@@ -137,3 +137,128 @@ old = '''
                 "blurred_self": it.rel in own_blur,'''
 new = '''
                 "blurred_self": it.blurred,'''
+
+# ---- folds: the heid code-review ("BLITZ-2") and bug-hunt ("FENRIR-6") panels on merge 1
+
+[[mutation]]
+label = "a board holding files loses the blur controls its labels point at"
+file = "booth/templates/booth.html"
+test = "tests/test_flow.py::test_a_board_with_files_gets_the_blur_controls_its_labels_point_at"
+old = '''
+  {% if all_items %}
+  {# The fog form IS a region'''
+new = '''
+  {% if not board %}
+  {# The fog form IS a region'''
+
+[[mutation]]
+label = "a blurred doc's own page renders clear"
+file = "booth/templates/doc.html"
+test = "tests/test_flow.py::test_a_blurred_docs_own_page_is_blurred_too"
+old = '''
+  <div class="docbody{% if blurred %} is-blurred{% endif %}" id="docbody">'''
+new = '''
+  <div class="docbody" id="docbody">'''
+
+[[mutation]]
+label = "the review offers Reveal all when only a doc (off the ring) is blurred"
+file = "booth/templates/view.html"
+test = "tests/test_flow.py::test_reveal_all_renders_where_it_can_act"
+old = '''
+    {% if film | selectattr('blurred') | list %}<button'''
+new = '''
+    {% if true %}<button'''
+
+[[mutation]]
+label = "the fog form is a GET (changes nothing with scripts off)"
+file = "booth/templates/booth.html"
+test = "tests/test_flow.py::test_the_booth_blur_toggle_works_without_js_and_lands_back_on_the_review"
+old = '''<form class="blur-all{% if booth_blurred %} is-on{% endif %}" method="post" action="/b/{{ name_url }}/blurbooth">
+    <input type="hidden" name="on" value="{{ '0' if booth_blurred else '1' }}">
+    <button title="{{ 'un-blur the whole booth — per-item'''
+new = '''<form class="blur-all{% if booth_blurred %} is-on{% endif %}" method="get" action="/b/{{ name_url }}/blurbooth">
+    <input type="hidden" name="on" value="{{ '0' if booth_blurred else '1' }}">
+    <button title="{{ 'un-blur the whole booth — per-item'''
+
+[[mutation]]
+label = "the swap stops carrying an item's own reveal"
+file = "booth/templates/base.html"
+test = "tests/test_flow_browser.py::test_an_items_own_reveal_survives_an_in_place_save"
+old = '''
+      ['revealed', 'is-closed'].forEach(function (c) {'''
+new = '''
+      ['is-closed'].forEach(function (c) {'''
+
+[[mutation]]
+label = "a storage READ that throws raises out of the pre-paint script"
+file = "booth/templates/base.html"
+test = "tests/test_flow_browser.py::test_reveal_all_never_shows_without_js_and_a_storage_failure_still_applies_the_click"
+old = '''
+    try {
+      if (b !== null && sessionStorage.getItem('booth.reveal:' + b) === '1') d.classList.add('reveal-all');
+    } catch (e) {}'''
+new = '''
+    if (b !== null && sessionStorage.getItem('booth.reveal:' + b) === '1') d.classList.add('reveal-all');'''
+
+[[mutation]]
+label = "fogging writes through a planted marker link"
+file = "booth/app.py"
+test = "tests/test_flow.py::test_fogging_never_writes_through_a_planted_marker_link"
+old = '''
+        try:
+            os.lstat(marker)
+            return True
+        except FileNotFoundError:
+            pass
+        try:
+            os.close(os.open(marker, os.O_WRONLY | os.O_CREAT | os.O_EXCL | os.O_NOFOLLOW, 0o644))
+        except FileExistsError:
+            pass                                   # lost a race to another fog: still fogged
+        return True'''
+new = '''
+        marker.touch(exist_ok=True)
+        return True'''
+
+[[mutation]]
+label = "the fog landing echoes `back` unchecked"
+file = "booth/app.py"
+test = "tests/test_flow.py::test_the_fog_landing_is_built_from_the_ring_never_echoed"
+old = '''
+        if back and back in review_chain(booth_items(booth)):'''
+new = '''
+        if back:'''
+
+[[mutation]]
+label = "the fog form is outside every region (a swap leaves its label stale)"
+file = "booth/templates/booth.html"
+test = "tests/test_flow.py::test_the_booth_blur_toggle_works_without_js_and_lands_back_on_the_review"
+old = '''
+  <span class="region-wrap" data-region="blur-booth"><form class="blur-all'''
+new = '''
+  <span class="region-wrap"><form class="blur-all'''
+
+[[mutation]]
+label = "Space on a focused review button moves to the next item"
+file = "booth/templates/view.html"
+test = "tests/test_flow_browser.py::test_space_on_a_focused_review_button_presses_it_and_does_not_move_on"
+old = '''e.target !== player && !(e.target.closest && e.target.closest('button, a, summary'))) {'''
+new = '''e.target !== player) {'''
+
+[[mutation]]
+label = "the top-bar controls squeeze into multi-line stacks at phone width"
+file = "booth/templates/base.html"
+test = "tests/test_flow_browser.py::test_the_review_and_doc_top_bars_fit_a_phone"
+old = '''
+  .blur-all button,.reveal-all-btn{white-space:nowrap}
+  @media (max-width:600px){.reveal-all-btn .ra-note{display:none}}'''
+new = '''
+'''
+
+[[mutation]]
+label = "the Desk strip under another booth's reveal is lifted by a whisker (blur(0px) is not blurred)"
+file = "booth/templates/base.html"
+test = "tests/test_flow_browser.py::test_reveal_all_on_booth_a_does_not_reveal_booth_b_or_the_desk"
+old = '''
+  .blurred-thumb{filter:blur(16px)}'''
+new = '''
+  .blurred-thumb{filter:blur(0px)}'''