{% comment %}
Shared page HEADER — the identity band rendered by BOTH top-level pages
(board_v3.html and chat.html), from this one file.

WHY IT IS A PARTIAL. Operator, 2026-07-29 (TG): the two pages' headers not
lining up is uncomfortable. They did not line up because each page rolled its
own header — the board's `.filterbar` was `padding: 8px 14px; min-height: 48px`
while the DM page's `header` was `padding: 10px 14px` with no min-height, so
the two bars were different heights and their contents sat on different
baselines. Two numbers kept in sync by hand is HOW they drifted; the fix is
structural, not a third number. This partial owns the band's markup and
page-header.css owns its geometry, so there is nothing left to keep in sync.

THE SWITCHER COMES FIRST — that is the operator's standing instruction
(「スイッチャーは左にそろえてください」, restated 2026-07-29 after the board and
the DM page had drifted to opposite sides). Its position is a property of THIS
file now, so the two pages cannot disagree about it: there is only one file to
read. Never give `.stx-cards-switcher` a `margin-left: auto` on a host page —
that pushes it right while leaving this markup looking correct, which is the
one way the instruction can silently come undone. `test__page_header_is_shared`
fails on both the ordering and the auto margin.

Callers pass the page they are on and the heading it wants:

    {% templatetag openblock %} include "scitex_cards/_page_header.html" with active="board" page_title="SciTeX Cards" {% templatetag closeblock %}

`api_base` and `scitex_cards_version` are inherited from the page context —
both views already provide them, and `api_base` is what `_page_switcher.html`
builds its mount-aware hrefs from (read its header before touching a link).

The `<h1>` carries NO class on purpose, and each host page already styles `h1`
inside its own header. NOTE both pages now pass the SAME `page_title` ("SciTeX
Cards"): the band names the PRODUCT and the switcher names the page. That is the
operator's 2026-07-30 instruction — a heading that changes between Board and DM
reads as the page breaking. `test__dm_naming_is_consistent.py` pins the stable
heading AND pins that the switcher still says DM, so the two pages cannot become
indistinguishable. page-header.css styles it
through `.stx-cards-header h1` so the typography is shared without the markup
having to say so.
{% endcomment %}
<div class="stx-cards-header">
  {% include "scitex_cards/_page_switcher.html" with active=active %}
  <h1>{{ page_title }}</h1>
  <span class="stx-cards-header__ver">v{{ scitex_cards_version|default:"?" }}</span>
</div>