fix v1.44.4: audit follow-up B2, B5, L4 sub-item

B2: the HTTP upload view failed OPEN when the config entry was
unavailable while the WS path failed closed — both now share one
may_write() policy helper (new auth.py) that denies non-admins when the
policy cannot be read.

B5: _finite now guards room rects, polygon vertices, view_box and
opening coordinates, not just layout positions; the declared
MAX_OPENINGS cap is finally enforced.

L4 (sub-item): every drag pipeline captures the pointer through the
tolerant helper (an inactive pointerId used to kill device/label/resize
drags); decor shapes gained a bounds clamp so they cannot be dragged far
outside the plan and persisted there.

+2 backend tests (16); both changelogs updated in this commit

custom_components/houseplan/http_api.py

@@ -19,7 +19,7 @@ except ImportError:  # older HA versions
 from homeassistant.core import HomeAssistant
 
 from .const import CONF_ADMIN_ONLY, CONTENT_URL, FILES_DIR, FILES_URL, PLANS_DIR
-from .store import get_entry
+from .auth import may_write
 from .validation import (
     FILE_EXTENSIONS,
     MAX_FILE_BYTES,
@@ -95,12 +95,8 @@ class HouseplanUploadView(HomeAssistantView):
 
     async def post(self, request: web.Request) -> web.Response:
         hass: HomeAssistant = request.app[KEY_HASS]
-        entry = get_entry(hass)
-        admin_only = bool(entry and entry.options.get(CONF_ADMIN_ONLY, False))
-        if admin_only:
-            user = request.get("hass_user")
-            if user is None or not user.is_admin:
-                return web.json_response({"error": "unauthorized"}, status=403)
+        if not may_write(hass, request.get("hass_user")):
+            return web.json_response({"error": "unauthorized"}, status=403)
 
         marker_id = "misc"
         filename: str | None = None