ember: add daily-focus-board canvas extension

Adds a canvas version of the daily-focus-board alongside the skill, addressing
@aaronpowell's review suggestion. The canvas renders the board in the Copilot
app and is backed by a JSON state file the assistant reads and writes, so you
can mark tasks done, add tasks, log progress, and recap your day from chat --
the file-backed "close the loop" upgrade over the localStorage skill.

The skill stays as the zero-install universal fallback for anyone not in the
Copilot app (same both-not-either pattern as the-workshop's signals-dashboard).

- extensions/daily-focus-board/: extension.mjs (canvas + session wiring) +
  board-core.mjs (loopback server, JSON state file, mutations, recap) +
  assets/board.html (file-backed UI) + preview.png + manifests.
- plugins/ember: register via x-awesome-copilot.extensions, bump 1.1.0 -> 1.2.0,
  add a Components row.

Note: assets/preview.png is a placeholder pending a real board screenshot.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Copilot-Session: cb356aa8-0af2-48f3-b3c6-8086c69d5308

plugins/ember/.github/plugin/plugin.json

@@ -1,7 +1,7 @@
 {
   "name": "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": "1.1.0",
+  "version": "1.2.0",
   "author": {
     "name": "jennyf19"
   },
@@ -24,5 +24,10 @@
     "./skills/from-the-other-side-quinn/",
     "./skills/from-the-other-side-vega/",
     "./skills/from-the-other-side-wiggins/"
-  ]
+  ],
+  "x-awesome-copilot": {
+    "extensions": [
+      "./extensions/daily-focus-board/"
+    ]
+  }
 }