fix(ui): section tabs above the breadcrumb, so the Ansible tab strip holds still (#5214)

The tabs were drawn in each page's content block, which base.html renders
after the breadcrumb, so on every nested Ansible page the strip moved down a
line. base.html now has a section_tabs block above the breadcrumb, and every
Ansible page fills it. A guard in test_breadcrumbs.py fails any page that calls
a tabs macro outside that block.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/test_breadcrumbs.py

@@ -53,3 +53,32 @@ def test_every_nested_page_has_a_trail():
     missing = sorted(name for name, p in pages.items()
                      if name not in TOP_LEVEL and needs_crumbs_and_lacks_them(p.read_text()))
     assert not missing, f"add {{% block breadcrumb %}}{{{{ crumbs([...]) }}}} (rule 134): {missing}"
+
+
+# A section's tabs go in base.html's section_tabs block, above the trail, so the
+# strip holds still whether or not the page has a breadcrumb (#5214). Drawn in
+# the content block instead, they sit under the trail and jump down a line on
+# every nested page.
+_TABS_BLOCK = re.compile(r"\{%-?\s*block\s+section_tabs\s*-?%\}(.*?)\{%-?\s*endblock", re.S)
+_TABS_CALL = re.compile(r"\{\{-?\s*\w*_tabs\(")
+
+
+def tabs_outside_their_block(text: str) -> bool:
+    calls = len(_TABS_CALL.findall(text))
+    inside = sum(len(_TABS_CALL.findall(b)) for b in _TABS_BLOCK.findall(text))
+    return calls > inside
+
+
+def test_the_tabs_guard_can_fail():
+    assert tabs_outside_their_block('{% block content %}{{ ansible_tabs("runs") }}{% endblock %}')
+    assert not tabs_outside_their_block('{% block section_tabs %}{{ ansible_tabs("runs") }}{% endblock %}')
+
+
+def test_section_tabs_sit_above_the_trail():
+    base = (REPO / "steward/templates/base.html").read_text()
+    assert base.index("{% block section_tabs %}") < base.index("{% block breadcrumb %}")
+    pages = [p for p in template_files() if _EXTENDS_BASE.search(p.read_text())]
+    tabbed = [p for p in pages if _TABS_CALL.search(p.read_text())]
+    assert len(tabbed) >= 10, [str(p) for p in tabbed]  # the ten Ansible pages, at least
+    wrong = sorted(str(p.relative_to(REPO)) for p in tabbed if tabs_outside_their_block(p.read_text()))
+    assert not wrong, f"move the tabs into {{% block section_tabs %}}: {wrong}"