Move WLED config tips to footer, add Web UI link, move preview to calibration

- Move WLED Configuration tips from Add Device modal to page footer
- Add WLED Web UI link in footer (auto-populated with first device URL)
- Add WLED Web UI button (globe icon) to device card actions
- Move pixel preview button from device card to calibration modal footer
- Add en/ru i18n keys for new UI elements

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

server/src/wled_controller/static/locales/en.json

@@ -40,6 +40,9 @@
   "devices.wled_config": "WLED Configuration:",
   "devices.wled_note": "Configure your WLED device (effects, segments, color order, power limits, etc.) using the",
   "devices.wled_link": "official WLED app",
+  "devices.wled_note_or": "or the built-in",
+  "devices.wled_webui_link": "WLED Web UI",
+  "devices.wled_note_webui": "(open your device's IP in a browser).",
   "devices.wled_note2": "This controller sends pixel color data and controls brightness per device.",
   "device.name": "Device Name:",
   "device.name.placeholder": "Living Room TV",
@@ -54,6 +57,7 @@
   "device.button.settings": "Settings",
   "device.button.calibrate": "Calibrate",
   "device.button.remove": "Remove",
+  "device.button.webui": "Open WLED Web UI",
   "device.status.connected": "Connected",
   "device.status.disconnected": "Disconnected",
   "device.status.error": "Error",