feat v1.42.1: room-card font sizes — 3 sliders with a live preview

- space.settings.card_font_scale (tier 2 base) + room.settings
  name_scale/label_scale (tier 3), 50-300%, multiplied together and
  stacking with resize-k and kiosk per-screen multipliers
- live sample card in both the space and room dialogs
- backend schema; smoke_font_scales.mjs (9 checks); docs same-commit

src/types.ts

@@ -10,6 +10,9 @@ export interface RoomCfg {
     /** 'device:<id>' or 'entity:<eid>'; unset = average over the room sensors. */
     temp_source?: string | null;
     hum_source?: string | null;
+    /** Font multipliers for THIS room's card (0.5-3, unset = 1). */
+    name_scale?: number | null;
+    label_scale?: number | null;
   } | null;
   id?: string;
   name: string;