feat: add batch write operations and unit test suite

[besart-finsweet]

Summary

• Add batch() method for performing multiple writes (set, update, delete) as a single atomic commit via the Firestore REST API
• Add unit test suite (47 tests) using Vitest + Firebase Emulator covering all existing modules: init, get, create, set, update, remove, query, and batch
• Add emulator support in get_firestore_endpoint via FIRESTORE_EMULATOR_HOST env var

Changes

• src/batch.ts — new batch() API with set, update, delete, and commit methods
• src/types.ts — added Write, CommitRequest, CommitResponse, WriteResult types
• src/utils.ts — emulator host detection for local development/testing
• vitest.config.ts + firebase.json + firestore.rules — test infrastructure
• src/*.test.ts + tests/unit/helpers.ts — integration tests for every module
• README.md — documented batch API and testing instructions

[Copilot]

Pull request overview

Adds a Firestore REST “write batch” API and introduces a Vitest + Firebase Emulator-based unit test suite, while also improving local/emulator endpoint support for Firestore requests.

Changes:

• Add batch() API supporting batched set, update, delete, and commit via the Firestore :commit REST endpoint.
• Add comprehensive unit tests (Vitest) that run against the Firestore emulator, plus supporting helper utilities and emulator config.
• Add FIRESTORE_EMULATOR_HOST support to get_firestore_endpoint and wire CI to run typecheck + unit tests.

Reviewed changes

Copilot reviewed 21 out of 23 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
vitest.config.ts	Configures Vitest to run node-based unit tests sequentially with emulator env vars.
tsconfig.json	Expands TS includes to cover tests and Vitest config for typechecking.
tests/unit/helpers.ts	Adds shared test helpers for initializing DB + clearing the emulator.
src/utils.ts	Adds emulator host support to Firestore endpoint construction.
src/types.ts	Introduces commit/batch-related REST types (Write, CommitRequest, etc.).
src/batch.ts	Implements the new batch() API and commit logic.
src/index.ts	Exports batch from the package entry point.
src/*.test.ts	Adds emulator-backed unit tests for all modules (init/get/create/set/update/remove/query/batch).
package.json	Adds unit-test scripts and dev deps for vitest + firebase-tools.
firebase.json	Adds Firestore emulator configuration (host/port + UI).
firestore.rules	Adds permissive rules for emulator testing.
.firebaserc	Sets a default local project id for emulator usage.
.github/workflows/ci.yml	Adds Typecheck + Unit-Tests jobs to CI workflow.
README.md	Documents the new batch API and how to run unit tests.
.changeset/lazy-trees-lie.md	Declares a minor release for the new feature/test suite.

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[Copilot]

Pull request overview

Copilot reviewed 21 out of 23 changed files in this pull request and generated 1 comment.

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[alexiglesias93]

looks great!