Support NextJS edge runtime (#618)

.changeset/config.json

.changeset/yellow-chicken-study.md

.github/workflows/test.yml

examples/readers/src/custom-simple-directory-reader.ts

packages/core/package.json

packages/core/src/agent/react/worker.ts

packages/core/src/agent/runner/base.ts

packages/core/src/embeddings/utils.ts

packages/core/src/index.edge.ts

packages/core/src/index.ts

packages/core/src/indices/keyword/index.ts

packages/core/src/indices/summary/index.ts

packages/core/src/indices/vectorStore/index.ts

...core/src/ingestion/strategies/UpsertsAndDeleteStrategy.ts

packages/core/src/readers/LlamaParseReader.ts

packages/core/src/readers/SimpleDirectoryReader.edge.ts

packages/core/src/readers/SimpleDirectoryReader.ts

packages/core/src/readers/TextFileReader.ts

packages/core/src/readers/index.ts

packages/edge/.gitignore