v1.51.0: explicit hide flags, the yellow principle, phone editor gestures, room button

The dev batch since v1.50.4, released as one:
- hiding is a per-device checkbox seeded once from the old filter
  (docs/FILTERING.md); blue ghosts under a local 'Show hidden' toggle
- yellow = doing its main job now; TRVs glow by hvac_action, service
  switches can no longer become a device's primary
- pinch/pan gestures in every editor on touch
- the room settings button: visual centre (inscribed circle + centroid
  pull), icon-derived size, zooms with the plan; metrics visible in the
  plan editor

Inventory: 147 frontend / 51 pure / 43 harness / 68 smokes.

package-lock.json

@@ -1,12 +1,12 @@
 {
   "name": "houseplan-card",
-  "version": "1.50.4",
+  "version": "1.51.0",
   "lockfileVersion": 3,
   "requires": true,
   "packages": {
     "": {
       "name": "houseplan-card",
-      "version": "1.50.4",
+      "version": "1.51.0",
       "license": "MIT",
       "dependencies": {
         "lit": "^3.1.3",