Prepare v1.75.0-beta.1

Seven version sources move together to 1.75.0-beta.1, both changelogs
close their section over what has landed since the stable v1.74.0, the
release notes carry the one shipped bullet on each side with the grouped
small-fixes bullet last, and STATUS says what this beta is.

What the user gets: the House Plan sidebar page can no longer serve a
previous version of the card. The panel entry fetched it through
`./houseplan-card.js` — a relative specifier, and relative resolution
does not inherit the `?v=` a dashboard gets from its Lovelace resource,
while the entry files carry no Cache-Control at all. A browser was free
to answer from its own heuristic cache for hours, and a stale loader
named a stale immutable chunk, so the panel ran an old card against the
current backend with nothing but the version banner to show for it —
and reloading could not help, because the address never changed (#535).

Internal in the line: #536 — the version banner now asks the host to
repaint when it drops the notice on disconnect, instead of leaving its
removal to whatever unrelated update happened to run next.

npm test 2532/2530/0 fail (the #349 manifest-tracking check goes green
with this commit), release contract green on all seven sources, bundle
287 323 B gzip inside the ceiling, docs strict green.

The `Release:` trailer is what asks CI for the heavy gates — smokes,
golden and the full performance comparison — on this exact SHA (#479).

Issue: #535
User-Visible: yes
Release: v1.75.0-beta.1

docs/RELEASE-NOTES.md

@@ -1,20 +1,16 @@
-<!-- release: v1.74.0 -->
+<!-- release: v1.75.0-beta.1 -->
 
 ## Основное
 
-- План стал заметно плавнее, а в Firefox разница разительная: фон «Следует за Солнцем» больше не перерисовывает весь лист на каждое движение мыши, перетаскивание сдвигает уже нарисованное вместо полной перерисовки, тень маркера не запускает анимацию сразу у всех значков, а переключение между этажами на большом плане перестало пересобирать маркеры самым долгим способом ([#532](https://github.com/Matysh/houseplan-card/issues/532), [#531](https://github.com/Matysh/houseplan-card/issues/531), [#524](https://github.com/Matysh/houseplan-card/issues/524), [#534](https://github.com/Matysh/houseplan-card/issues/534)).
-- Печатный план стал крупнее примерно на треть: размеры встали на сам чертёж, а столбец выносов сбоку убран ([#530](https://github.com/Matysh/houseplan-card/issues/530)).
-- План, доставшийся от времён «комнат без стен», снова редактируется: наследие снимается при первом сохранении, а не запирает план наглухо ([#529](https://github.com/Matysh/houseplan-card/issues/529)).
+- Пункт меню House Plan больше не застревает на прошлой версии карточки: он тянул её по единственному адресу без версии, и браузер был вправе часами отдавать копию из кэша ([#535](https://github.com/Matysh/houseplan-card/issues/535)).
 - Мелкие исправления и улучшения.
 
 ## Highlights
 
-- The plan is noticeably smoother, and in Firefox the difference is dramatic: the “Follows the sun” background no longer repaints the whole sheet on every mouse move, dragging shifts what is already drawn instead of redrawing it, a marker's shadow no longer restarts an animation on every marker at once, and switching floors on a large plan stopped rebuilding the markers the slow way ([#532](https://github.com/Matysh/houseplan-card/issues/532), [#531](https://github.com/Matysh/houseplan-card/issues/531), [#524](https://github.com/Matysh/houseplan-card/issues/524), [#534](https://github.com/Matysh/houseplan-card/issues/534)).
-- The printed plan is about a third larger: the dimensions now sit on the drawing itself and the separate column beside it is gone ([#530](https://github.com/Matysh/houseplan-card/issues/530)).
-- A plan left over from the era of “rooms without walls” can be edited again: the leftover is cleaned up on the first save instead of locking the plan completely ([#529](https://github.com/Matysh/houseplan-card/issues/529)).
+- The House Plan sidebar page no longer gets stuck on a previous version of the card: it fetched the card through the one address that carries no version, and a browser was free to serve a cached copy for hours ([#535](https://github.com/Matysh/houseplan-card/issues/535)).
 - Small fixes and improvements.
 
 Сообщество / Community: [Telegram](https://t.me/ha_houseplan)
 
-[Полный список изменений на русском](https://github.com/Matysh/houseplan-card/blob/v1.74.0/docs/CHANGELOG.ru.md)
-· [Full changelog in English](https://github.com/Matysh/houseplan-card/blob/v1.74.0/docs/CHANGELOG.md)
+[Полный список изменений на русском](https://github.com/Matysh/houseplan-card/blob/v1.75.0-beta.1/docs/CHANGELOG.ru.md)
+· [Full changelog in English](https://github.com/Matysh/houseplan-card/blob/v1.75.0-beta.1/docs/CHANGELOG.md)