canvas-extension: new chat cards extension (#2698)

* canvas-extension: new chat cards extension

* codespell: resolve mispelling

* code review, debug extension finding github app issue

* Apply suggestions from code review

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

* Apply suggestions from code review

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

* apply edits from code review

* apply edits from code review

* apply edits from code review

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Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

plugins/chat-cards/README.md

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+# Chat Cards Plugin
+
+Interactive card deck for GitHub Copilot canvas. Instead of walls of text, the
+agent explains things visually with a live deck of interactive cards: tab boxes,
+tables, SVG charts, forms, collapsible sections, numbered outlines, rendered
+markdown documents, and short video clips. Forms are two-way: submitting one
+sends the values back to the conversation as the agent's next prompt, so a card
+can gather context and steer the session as easily as it presents information.
+
+## Installation
+
+```bash
+copilot plugin install chat-cards@awesome-copilot
+```
+
+## Source
+
+This plugin is part of [Awesome Copilot](https://github.com/github/awesome-copilot).
+
+## License
+
+MIT

plugins/chat-cards/plugin.json

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+{
+  "$schema": "https://agent-plugins.org/schemas/1.0.0/plugin.schema.json",
+  "name": "chat-cards",
+  "description": "Interactive card deck in a GHCP canvas: tab cards, tables, SVG charts, show/hide sections, numbered outlines, rendered markdown documents, video clips, and forms whose submissions come back to the conversation as prompts.",
+  "version": "0.1.0",
+  "keywords": [
+    "interactive-cards",
+    "charts",
+    "forms",
+    "education",
+    "visual-explanations"
+  ],
+  "author": { "name": "John Haugabook" },
+  "repository": "https://github.com/github/awesome-copilot",
+  "license": "MIT",
+  "extensions": {
+    "com.github.copilot": {
+      "logo": "assets/preview.png"
+    },
+    "com.github.awesome-copilot": {
+      "extensions": [
+        "./extensions/chat-cards"
+      ]
+    }
+  }
+}