feat: add color picker confirmation

Issue: #476
User-Visible: yes

docs/CHANGELOG.md

@@ -2,6 +2,11 @@
 
 ## Unreleased
 
+- Every color picker now has a clear full-width **OK** button. Colors and
+  opacity still apply live, while invalid HEX input stays open for correction
+  instead of being accepted accidentally
+  ([#476](https://github.com/Matysh/houseplan-card/issues/476)).
+
 ## v1.73.0-beta.1 — 2026-09-06
 
 - Active Zigbee topology links and route bubbles now stay readable above room

docs/CHANGELOG.ru.md

@@ -8,6 +8,11 @@
 
 ## Не выпущено
 
+- Во всех окнах выбора цвета появилась понятная полноширинная кнопка **«ОК»**.
+  Цвет и прозрачность по-прежнему применяются сразу, а при некорректном HEX
+  окно остаётся открытым, чтобы значение можно было исправить
+  ([#476](https://github.com/Matysh/houseplan-card/issues/476)).
+
 ## v1.73.0-beta.1 — 2026-09-06
 
 - Активные линии и подписи Zigbee-топологии теперь читаются поверх названий

docs/TESTING.md

@@ -446,6 +446,15 @@
       labels through the unchanged color/opacity event contract, and the shared
       component contains no native `input[type=color]`
       [unit: `color-picker.test.mjs`].
+- [ ] The localized full-width OK button is the final picker control, remains at
+      least 40 CSS px high in native and fallback surfaces, and closes without a
+      duplicate value event or click-through to the parent card
+      [unit: `color-picker.test.mjs`, auto: `smoke_color_picker.mjs`,
+      `smoke_help_affordance.mjs`].
+- [ ] Invalid HEX keeps the picker open and focused on its error even after a
+      repeated OK; only new valid HEX input unlocks confirmation, while live
+      color/opacity updates and the existing outside/trigger/Escape close paths
+      retain their values [auto: `smoke_color_picker.mjs`].
 - [ ] At 390 px the one surface exposes hue, saturation, brightness, HEX and
       opacity without horizontal overflow; keyboard Shift+Arrow, touch pointer
       cancellation, invalid HEX recovery, Escape focus return and disabled mode