Default room border/name colour: dark grey #55606c (was accent #3ea6ff)

Owner call 2026-08-03: the resolved default for spaces without an explicit
room_color is now a dark slate grey — reads on the white paper of drawn
plans and on the glow-dark theme. Spaces where the colour was ever chosen
keep their stored room_color; editor accents, resize handles, marker
ripple default and the compass needle stay on the accent colour.
Pinned defaults updated in test/logic.test.mjs and smoke_space_settings.

demo/smoke_space_settings.mjs

@@ -58,6 +58,6 @@ checkAll(res, {
   "atticSquare": true,
   // fill_mode 'glow' — the default for NEW spaces since v1.54 (owner call).
   // Existing spaces with an absent fill_mode still resolve to 'none'.
-  "atticSettings": {"show_borders": true, "show_names": true, "room_color": "#3ea6ff", "room_opacity": 0.55, "fill_mode": "glow", "temp_min": 20, "temp_max": 25, "show_lqi": true, "label_temp": false, "label_hum": false, "label_lqi": false, "label_light": false},
+  "atticSettings": {"show_borders": true, "show_names": true, "room_color": "#55606c", "room_opacity": 0.55, "fill_mode": "glow", "temp_min": 20, "temp_max": 25, "show_lqi": true, "label_temp": false, "label_hum": false, "label_lqi": false, "label_light": false},
 });
 await finish(browser, res);

src/logic.ts

@@ -837,7 +837,13 @@ export interface SpaceDisplay {
   bgColor: string | null;
 }
 
-export const DEFAULT_ROOM_COLOR = '#3ea6ff';
+// Default for borders + room names when room_color is absent. Dark slate
+// grey since 2026-08-03 (owner call, was the accent '#3ea6ff'): reads on
+// the white paper of drawn plans and on the glow-dark theme alike.
+// CHANGELOG draft: "Default room border/name colour is now dark grey
+// (#55606c). Spaces with an explicitly chosen room_color keep it; only
+// spaces that never touched the colour pick up the new default."
+export const DEFAULT_ROOM_COLOR = '#55606c';
 export const DEFAULT_ROOM_OPACITY = 0.55;
 export const DEFAULT_TEMP_MIN = 20;
 export const DEFAULT_TEMP_MAX = 25;

test/logic.test.mjs

@@ -245,7 +245,7 @@ test('spaceDisplayOf: defaults differ for spaces with and without a plan', () =>
   assert.equal(s.opacity, 1);
   assert.equal(s.fill, 'lqi');
   const g = spaceDisplayOf({ settings: { room_color: 'javascript:alert(1)', fill_mode: 'weird' } });
-  assert.equal(g.color, '#3ea6ff');
+  assert.equal(g.color, '#55606c'); // dark-grey default since 2026-08-03
   assert.equal(g.fill, 'none');
 });