feat(FN-3739): add fusion-plugin-even-cards workspace plugin

- Add a new fusion-plugin-even-cards package with typed card formatting utilities and board/task card generation
- Implement authenticated plugin routes for board card endpoints and plugin registration wiring
- Add unit tests for auth handling, board routes, and card formatting behavior
- Document plugin in PLUGIN_AUTHORING guide and register it in pnpm workspace

Fusion-Task-Id: FN-3739

docs/PLUGIN_AUTHORING.md

@@ -1143,6 +1143,13 @@ Example plugin demonstrating settings schema and runtime configuration with all
 - Features: Configurable greeting message, tag limit, logging toggle, log level selector
 - **Install from Settings**: Designed to be installed via the dashboard Settings → Plugins UI
 
+### [Even Cards Plugin](../../plugins/fusion-plugin-even-cards/)
+
+Read-only board/task card projection plugin for Even Realities companion flows.
+
+- Demonstrates: plugin routes protected with API-key auth, store reads via `ctx.taskStore`, and card-deck projection helpers
+- Features: `GET /board/cards`, `GET /board`, and `GET /tasks/:id/cards` endpoints with compact card payloads
+
 ### Installing Example Plugins from Settings
 
 All example plugins can be installed via the dashboard Settings → Plugins UI: