fix(desk): a row's keep, release and wipe take no room of their own

Operator, on the live Desk: "release and x take up space whether or not
they're visible." They sat in a side column at opacity 0, which hides a
control and still reserves its box, and hover-only never worked on
touch.

Each control now sits on the facts line beside the state it changes:
release after "kept", keep after a countdown or hold, wipe last. They
are always visible and quiet, and wipe turns danger only under the
pointer or focus. The side column renders only when the row carries a
badge. The row is flex, so an absent column costs no gap. Forms, POST
targets and data-confirm wording are unchanged.

The flex row exposed a latent sizing bug: the stacked Desk column was a
bare 1fr, whose minimum is its content's, so a long nowrap provenance
line scrolled the page sideways at phone width (1029px at 390). It is
now minmax(0,1fr).

Both behaviours have browser tests, mutation-proved (r2_flow.toml:
21/21). Contract C4 amended.

tests/mutations/r2_flow.toml

@@ -158,3 +158,32 @@ new = '''
                 continue
         except FileNotFoundError:
             continue'''
+
+[[mutation]]
+label = "Desk row controls hidden until hover again (opacity 0 keeps their box)"
+file = "booth/templates/base.html"
+test = "tests/test_flow_browser.py::test_a_rows_keep_release_and_wipe_take_no_room_of_their_own"
+old = '''
+  .desk-facts form{display:inline;margin:0}'''
+new = '''
+  .desk-facts form{display:inline;margin:0;opacity:0}'''
+
+[[mutation]]
+label = "Desk row renders its side column with no badge in it (a reserved gap)"
+file = "booth/templates/index.html"
+test = "tests/test_flow_browser.py::test_a_rows_keep_release_and_wipe_take_no_room_of_their_own"
+old = '''
+    {% if b.marks_open or b.hold == "unreadable" or section == 'new' or b.uploaded %}
+    <div class="desk-side">'''
+new = '''
+    {% if true %}
+    <div class="desk-side">'''
+
+[[mutation]]
+label = "the stacked Desk column is a bare 1fr (content sets its minimum)"
+file = "booth/templates/base.html"
+test = "tests/test_flow_browser.py::test_the_desk_never_scrolls_sideways_on_a_phone"
+old = '''
+  @media (max-width:1000px){.desk{grid-template-columns:minmax(0,1fr)}}'''
+new = '''
+  @media (max-width:1000px){.desk{grid-template-columns:1fr}}'''