Add clone support for all entity types

Clone button on every card opens the editor in create mode pre-filled
with copied data and a "(Copy)" name suffix. Cancelling discards the
clone — entity is only persisted on Save.

Supported: LED targets, color strip sources, KC targets, pattern
templates, picture sources, capture templates, PP templates.

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

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

@@ -237,6 +237,7 @@
   "common.loading": "Loading...",
   "common.delete": "Delete",
   "common.edit": "Edit",
+  "common.clone": "Clone",
   "streams.title": "\uD83D\uDCFA Sources",
   "streams.description": "Sources define the capture pipeline. A raw source captures from a display using a capture template. A processed source applies postprocessing to another source. Assign sources to devices.",
   "streams.group.raw": "Screen Capture",