T7.2 - F6/D3: the form gets structure - a section rail, one section open

F6 as amended by D3 (Aug 18): one page, persistent side navigation, sections
collapsible, only the current one open by default, plus Expand all. Tabs were
rejected in D3 because they hide sections a first-time author does not know
exist.

What changed:
- The jump-chip strip (#section-nav, span onclick) is gone. In its place a
  <nav> section rail of real <button> entries, aria-current on the current
  section, 44px tap targets, above the form at 390px and beside it at 1440px.
- Every section heading is now a disclosure <button> with aria-expanded and
  aria-controls. One section open at rest; Expand all (aria-pressed) opens
  everything and is remembered per browser.
- Sections are URL-addressable (?section=, T4.2 machinery) and a deep link to
  a collapsed section expands it. Positional-id fallback removed: a card
  without an id gets a console.error and no rail entry, never an invented
  sec-N id that would ride into shareable URLs and move between visits.
- General Information (1,288px on its own) split into #general-card and
  #assign-card (Assignment & Schedule). The split is presentational: both
  cards are the ONE CR-006 section `general` (WP_SECTION_NODES lists both),
  so wp-sections.js and the SOP wizard are untouched. CR-001's adjacency
  (P6 activity beside due date) is preserved and asserted.
- gotoSection() flushes autosave, which the deleted chips used to do.
- secMakeToggle() preserves every element child of a heading - help tips go
  outside the button, everything else inside the label. The first version
  cleared textContent and destroyed #saved-count, which killed boot one line
  short of wpCreatorReady with the page still visibly rendered.
- BL-013 folded in per the task: the T3.4 focus ring on the rebuilt form.
  frame_check reports outline solid 2px on creator inputs.

Height, measured not asserted: 5,399px before; 1,995px at rest at 1440x900.

DONE-WHEN NOT FULLY MET - stated per CLAUDE.md rather than marked complete:
"no single view exceeds roughly two screen heights at rest" reads 2.22
screens (1995/900). The remaining gap is page chrome this wave reworks:
.ctx-bar (67px, T7.4) and .release-banner (45px, T7.5). The criterion was
already amended once (D3, "at rest") and is not being moved again to fit;
tests/form_structure_check.py keeps the check red and it is re-measured at
the end of wave 7. Every other done-when entry passes.

Backlog: BL-001's cause corrected a third time - at rest the overflow is
help.js's .help-tip::after tooltip (481 vs 390), the S8 component T9.5
rebuilds; the tables still overflow only when expanded. Deliberately not
fixed here - a fix would be thrown away with the component at T9.5.

Verification (each probe run alone): form_structure_check 50/51 (the height
check above), sections_check 95/95, generalinfo_check 49/49, frame_check
39/39 regression pass.

Items: F6, D3, BL-013, BL-001 (re-measured)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/generalinfo_check.py

@@ -182,11 +182,20 @@ def run(page, base, tok):
           const p6 = document.getElementById('wp_p6_id').closest('.field');
           return due.nextElementSibling === p6;
         })()"""))
-    chk("...inside General Information, so the CR-006 toggle governs them",
+    # Re-pointed at T7.2, not relaxed. This used to assert DOM containment in
+    # #general-card, and T7.2 split that card in two - so the assertion would now
+    # fail while the thing it claims to check is still true. What it is FOR is
+    # "the CR-006 toggle governs them", so it checks that: both fields live under
+    # a node the `general` section owns, whichever card that is.
+    chk("...owned by the General Information section, so its CR-006 toggle governs them",
         page.eval("""(() => {
-          const card = document.getElementById('general-card');
-          return card.contains(document.getElementById('wp_p6_id'))
-              && card.contains(document.getElementById('wp_p6_desc'));
+          const owners = ['#general-card', '#assign-card']
+            .map(sel => document.querySelector(sel)).filter(Boolean);
+          const covered = id => {
+            const el = document.getElementById(id);
+            return !!el && owners.some(o => o.contains(el));
+          };
+          return covered('wp_p6_id') && covered('wp_p6_desc');
         })()"""))
 
     print("   they persist, and survive a reload")