feat: initial project structure and generate API types

Initialized `package.json`, add tsup build config (CJS/ESM/DTS), wire up
full Makefile targets (lint/test/check/build), add missing BadRequest
response component to OpenAPI spec, generate TypeScript types from spec,
configure biome to exclude generated files, and add `@types/ws`

AGENTS.md

@@ -0,0 +1,67 @@
+# AGENTS.md
+
+## Project
+
+Wrenn JavaScript SDK — a client library for the Wrenn microVM platform. e2b drop-in replacement.
+Package name: `@wrenn/sdk`. Node.js 18+, TypeScript 5.5+, managed with [pnpm](https://pnpm.io/).
+
+## Commands
+
+```bash
+pnpm install                          # install deps
+make lint                             # biome check + format check (no auto-fix)
+make test                             # unit tests only (vitest)
+make test-integration                 # all tests including integration (needs live server)
+make generate                         # regenerate types from OpenAPI spec (openapi-typescript)
+make check                            # lint + unit test
+make build                            # tsup build (CJS + ESM + DTS)
+```
+
+- `make test` runs all non-integration tests. To run a specific test file: `pnpm vitest run tests/commands.test.ts`
+- No separate typecheck step — `vitest` and `tsup` handle type checking during test/build. `tsc --noEmit` is available but not wired up in CI.
+
+## Architecture
+
+- `src/` — the library package
+  - `capsule.ts` — high-level `Capsule` class (main user-facing class)
+  - `client.ts` — low-level `WrennClient` with `CapsulesResource` and `SnapshotsResource`
+  - `commands.ts` — command execution, streaming, and background process management
+  - `files.ts` — filesystem operations
+  - `pty.ts` — interactive terminal (PTY) over WebSocket
+  - `exceptions.ts` — typed error hierarchy (`WrennError` base)
+  - `models/generated.ts` — **auto-generated** from OpenAPI spec via `openapi-typescript` (never edit directly; run `make generate`)
+  - `git/` — git operations inside capsules (clone, push, pull, status, branches, etc.)
+  - `code-interpreter/` — specialized capsule for stateful Jupyter kernel execution
+  - `_shared/http.ts` — thin `fetch` wrapper with auth headers, base URL, and error mapping
+  - `_shared/websocket.ts` — WebSocket helper wrapping `ws`
+  - `config.ts` — constants (`DEFAULT_BASE_URL`, env var names)
+- `tests/` — unit tests use `msw` to mock HTTP; integration tests are in `tests/integration/`
+- `api/openapi.yaml` — OpenAPI spec used for type generation
+
+## Key Conventions
+
+- Generated types live in `src/models/generated.ts`. Never edit them. Run `make generate` to update.
+- No sync/async split — JS is naturally async. One `Capsule` class, all methods return `Promise`.
+- `Sandbox` is a deprecated alias for `Capsule`. New code should use `Capsule`.
+- Uses native `fetch` for HTTP (Node 18+), `ws` for WebSockets, `zod` for runtime validation.
+- Resource disposal via `Symbol.asyncDispose` (`await using`). Also supports manual `.close()`.
+- Streaming methods return `AsyncGenerator` (e.g. `commands.stream()`, `files.downloadStream()`).
+- Static + instance method pattern: `capsule.destroy()` (instance) and `Capsule.destroy(id, opts)` (static).
+
+## Testing
+
+- Unit tests mock HTTP via `msw` (Mock Service Worker for Node).
+- Integration tests require env vars: `WRENN_API_KEY` (or `WRENN_TOKEN`), optionally `WRENN_BASE_URL`.
+- Integration test fixtures in `tests/integration/setup.ts` create real capsules and clean them up.
+- Tests use `vitest` — no `@jest` globals. Use `import { describe, it, expect } from 'vitest'`.
+
+## CI
+
+Woodpecker CI (`.woodpecker/check.yml`) runs on push to `main` and `dev`:
+1. `make lint`
+2. `make test`
+3. `make test-integration`
+
+## Dependencies
+
+Runtime: `ws` (WebSocket), `zod` (validation). Everything else is dev-only.