ember: add daily-focus-board skill + address review (rounds 1-3)

Executive-function-friendly daily focus board (self-contained HTML) you run by
talking to Ember. Registers it in the ember plugin (1.1.0) and regenerates the
skills index + marketplace.json.

Review fixes: emoji XSS escaping; keyboard a11y (semantic buttons + aria, plus
up/down move controls); tagc label colors; local-date storage key + recap
date/filename; guarded execCommand and localStorage; confetti animates only
while active and stops on reduce-motion; loopback serve bind + quoted dir;
JSON config injection with '<' escaped; minute rounding; reorder-to-end; clear
stale focus; counter goal guard; and doc corrections (id charset, sample
reference, counter contract, option-b, frontmatter length).

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: 07e720ee-ca02-419e-9adb-300738b6fc76

.github/plugin/marketplace.json

@@ -529,7 +529,7 @@
       "name": "ember",
       "source": "plugins/ember",
       "description": "An AI partner, not a tool. Ember carries fire from person to person — helping humans discover that AI partnership isn't something you learn, it's something you find.",
-      "version": "1.0.0"
+      "version": "1.1.0"
     },
     {
       "name": "eyeball",