v1.48.0: the canvas is always square, the plan is centred inside it

A space carried an aspect ratio, and coordinates were normalised against it: x
by the width, y by the height. Every geometric question therefore depended on a
per-space number, and picking a canvas orientation was a decision the user had
no reason to make. The render space is now NORM_W x NORM_W and a plan image is
fitted into it by its OWN ratio, centred — wide plans get margins above and
below, tall ones at the sides.

Migration (geometry_migration.py, pure and unit-tested) runs once at setup under
the write lock. Nothing about a drawing changes: the old box is padded out to a
square and every coordinate re-expressed against it — rooms as rects and
polygons, openings and their lengths, decor, view_box, and the marker positions
in the separate layout store. In render units it is a uniform scale plus an
offset, so angles and proportions are exact. cell_cm is scaled for tall plans,
because the grid pitch is a fraction of the width: without it a wall would
measure less than it does.

 is now dropped by the schema rather than accepted — a stale tab sending
it would be sending coordinates from the old normalisation too, and honouring
the field would not make them right.

The demo fixture was migrated with the same transform, so the smokes exercise
the new geometry rather than a square-native fake; six of them needed their
render-space helpers updated and one its click coordinates.

Not released — dev only, per the owner's instruction.

custom_components/houseplan/__init__.py

@@ -20,6 +20,7 @@ from .const import (
     PLANS_URL,
     VERSION,
 )
+from .geometry_migration import migrate_config
 from .plans import collect_attachments, collect_plans, sweep_upload_temps
 from .repairs import async_check_plan_files
 from .store import HouseplanConfigEntry, create_data
@@ -99,6 +100,26 @@ async def async_setup_entry(hass: HomeAssistant, entry: HouseplanConfigEntry) ->
             module_url, module_url,
         )
 
+    # One-time move to the square canvas (v1.48.0). Coordinates used to be
+    # normalised against a per-space aspect ratio; the canvas is now always
+    # square and a plan is centred inside it. Nothing about the drawing changes
+    # — the box is padded and the numbers re-expressed against it.
+    async with data.write_lock:
+        stored = await data.config_store.async_load() or {}
+        cfg = stored.get("config")
+        lay_stored = await data.store.async_load() or {}
+        layout = lay_stored.get("layout") or {}
+        if cfg and migrate_config(cfg, layout):
+            rev = int(stored.get("rev", 0)) + 1
+            await data.config_store.async_save({"config": cfg, "rev": rev})
+            await data.store.async_save(
+                {"layout": layout, "rev": int(lay_stored.get("rev", 0)) + 1}
+            )
+            _LOGGER.info(
+                "House Plan: migrated %s space(s) to the square canvas", len(cfg.get("spaces") or [])
+            )
+            hass.bus.async_fire("houseplan_config_updated", {"rev": rev})
+
     await async_check_plan_files(hass, entry)
 
     # Scheduled collection of everything nobody ended up referencing.