feat v1.39.0: pure light sources toggle on click by default

- resolveTapAction: no explicit action + domain light -> toggle (kettle
  et al. keep info via their non-light primary); explicit choice wins
- device dialog shows the effective default (defaultTap)
- unit tests updated (+1, 106); smoke_light_default_tap.mjs; docs
  same-commit

docs/CHANGELOG.md

@@ -1,5 +1,13 @@
 # Changelog
 
+## v1.39.0 — 2026-07-23 (lights toggle by default)
+- Pure light sources — devices whose primary entity is a `light` (bulbs,
+  chandeliers, night lights, light groups) — now **toggle on click by
+  default**, right from auto-placement, no per-device setting needed.
+  Devices where light is a side function (a kettle's backlight: its primary
+  is a sensor) keep the Device-card default. An explicit per-device choice
+  always wins. The device dialog shows the effective default.
+
 ## v1.38.4 — 2026-07-23
 - Plan editor: the DERIVED wall segments (the markup layer's solid lines)
   are now trimmed under open boundaries as well — v1.38.3 only trimmed the

docs/TESTING.md

@@ -140,6 +140,12 @@ Run the *core flows* (marked ★ below) in each environment at least once per mi
       (explicit ripple color still wins); off/white lights unchanged [auto]
 - [ ] Alarm pulse (v1.27.0): leak/smoke/gas/CO/siren in 'on' pulse a red ring over any
       display mode; clears on 'off'; unavailable never alarms [auto]; reduced-motion static
+- [ ] Lights toggle by default (v1.39.0): a device whose PRIMARY entity is a
+      light (bulbs, chandeliers, night lights, light groups) toggles on click
+      out of the box — no per-device setting needed; the device dialog shows
+      "Toggle" as its effective default; devices where light is a side
+      function (kettle: primary = sensor) keep the Device-card default;
+      explicit per-device "Device card" wins over the default [auto]
 - [ ] Derived walls cut too (v1.38.4): in the Plan editor the derived wall
       segments (.seg) no longer run solid through an open stretch — only the
       dash remains there [auto]