feat: experimental package + json query engine (#613)

.changeset/clever-doors-invite.md

package.json

packages/core/src/agent/types.ts

packages/core/src/index.ts

packages/experimental/.cjs.swcrc

packages/experimental/.swcrc

packages/experimental/CHANGELOG.md

packages/experimental/examples/jsonQueryEngine.ts

packages/experimental/examples/package.json

packages/experimental/jsr.json

packages/experimental/package.json

packages/experimental/src/engines/query/JSONQueryEngine.ts

packages/experimental/src/engines/query/index.ts

packages/experimental/src/engines/query/prompt.ts

packages/experimental/src/index.ts

packages/experimental/tsconfig.json

pnpm-lock.yaml

tsconfig.json