v1.49.0: content-fit zoom, swipe animation, wording, and the v1.47.0 review

Owner's batch:
- zoom now opens on what is DRAWN (rooms + 5% margin) for spaces with no
  background image; with one the image is the plan and still fits whole. A small
  plan on the square canvas no longer opens as a speck.
- swiping between spaces, and the kiosk carousel, slide sideways; honours
  prefers-reduced-motion.
- the room settings button reads 'Room settings' and lightens on hover.
- 'curation' is filtering everywhere: UI strings, docs, code.

Checked the yard while I was there: its drawing sits off-centre because it was
drawn that way — before the migration x spanned 0.12..0.54 with 0.12 and 0.46 of
margin. The migration added 0.1465 on each side, symmetrically. Content-fit zoom
makes it moot anyway.

From the v1.47.0 review:
- HP-1470-02: the picker let you delete the plan you had just selected — it is
  not in the stored config yet, so the server rightly called it free, and the
  save then stored a url with no file. The button is disabled, and since two
  clients can do this in either order, config/set now verifies every internal
  plan url against the disk under the write lock and answers .
  External and legacy urls are not ours to police.
- HP-1470-01: growth is bounded at the door rather than by deleting old files —
  that mistake cost real plans twice. check_quota refuses an upload that would
  push the store past 256 MB / 200 plans (1 GB / 1000 attachments) or leave less
  than 512 MB free. The plan list is capped at 60 newest with a total, and
  thumbnails load lazily.
- HP-1470-03: picking a saved plan waited for nothing and stored a fallback
  ratio when the signature had not arrived — a square plan came out stretched.
  It waits for the signature, binds the result to the dialog that asked, and the
  dialog preview is signed too.
- report §5: the last lifecycle comments still described age-based collection.

Not released yet — the owner asked for a release once the batch is done.

src/i18n/en.json

@@ -21,7 +21,7 @@
   "title.zoom_out": "Zoom out",
   "title.zoom_reset": "Reset zoom",
   "title.add_device": "Add a device to the plan",
-  "title.show_all": "Show all area devices (no curation)",
+  "title.show_all": "Show all area devices (no filtering)",
   "title.markup": "Room markup: grid, lines, outlines",
   "title.configure_space": "Configure space",
   "title.add_space": "Add space",
@@ -323,7 +323,7 @@
   "room.label_scale": "Metrics size",
   "preview.room_name": "Living room",
   "toast.cfg_reload_failed": "Could not reload the plan from the server: {err}",
-  "room.settings_short": "Room",
+  "room.settings_short": "Room settings",
   "room.unnamed": "Unnamed room",
   "marker.is_light": "This device is a light source",
   "marker.is_light_tip": "Makes the icon glow in the “Light sources” fill even without a light entity — for a smart switch driving ordinary fixtures. The glow follows the switch (or the lights bound above).",