fix: emit #/$defs/ refs in set_tasks schema

TypeBox Type.Cyclic generates bare local refs ("AddTask") which strict
moonshot-flavored JSON Schema gateways (Console Go upstream) reject with
HTTP 400. Rewrite all local $ref values to the #/$defs/ form after
building the schema, and add a regression test asserting the ref format.

Bump version to 0.2.2.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "pi-todo-herdr",
-  "version": "0.2.1",
+  "version": "0.2.2",
   "description": "Hierarchical task tools for Pi with a live widget and Herdr sidebar integration.",
   "type": "module",
   "main": "./index.ts",