refactor(e2b): narrow the sandbox POC

AGENTS.md

@@ -12,8 +12,9 @@ DeepSeek Harness SDK is a plugin-based agent harness on vendored Cordis: **every
 vendor/      Vendored Cordis source — manifest + sync procedure in vendor/README.md
 packages/    @deepseek-ai/dsh-<pkg> workspaces at packages/<group>/<pkg>/
   core/        product API spine: session, system-prompt, tools, agent, agent-loop
+  typert/      type graph generator, loader, and runtime registry
   llm/         LLM seam + DeepSeek adapters (direct-fetch + pi-ai design twin)
-  e2b/         remote-runtime POC
+  e2b/         E2B POC: sandbox owner + FS/subprocess adapters
   bash/        bash executor seam + local impl + model-facing bash tools
   subprocess/  subprocess seam + local process-tree impl
   pty/         persistent PTY seam/backend/tools
@@ -90,7 +91,7 @@ Real-API tests and demos read `DEEPSEEK_API_KEY`, optional `DEEPSEEK_BASE_URL`,
 ## Conventions
 
 - Every npm package is `@deepseek-ai/dsh-<name>`; vendored packages keep upstream names and are `private: true`. `cordis` is a peerDependency (+ dev) of every harness package.
-- ESM everywhere (`"type": "module"`). Cross-package imports use package names; in-package relative imports include `.ts`. CI subprocesses that boot examples or Cordis configs run built `lib/` under plain Node; only explicit source-path regressions use tsx ([testing policy](docs/testing.md#test-subprocess-launch-modes)).
+- ESM everywhere (`"type": "module"`). Cross-package imports use package names; in-package relative imports include `.ts`. Config subprocesses run built `lib/` under plain Node; source regressions use their declared launcher ([testing policy](docs/testing.md#test-subprocess-launch-modes)). The `dsh` CLI source launch runs through tsx's ESM-only hook (`node --import tsx/esm`); modules it reaches must stay ESM (no CJS-only shapes) — Node's native TypeScript modes are unavailable across the engines range ([source-launch contract](.agents/notes/implemented/architecture/2026-07-29-dsh-source-launch-tsx-esm.md)). TUI/Web `cordis.yml` bare plugins must appear in their resolver manifest's `dependencies`; `verify-cordis-config` enforces it.
 - **Registrations are effects**: every contribution goes through `ctx.effect()` / `ctx.on()`; a registry's `register()` returns the disposer.
 - **Runtime invariants assert owned relationships.** Check authoritative event streams or mutable data, not service or method presence, plugin metadata or effects, or fixed pure examples. If a package has no plausible relationship, an explained empty companion is correct ([package contract](packages/AGENTS.md)).
 - **Typed events use declaration merging** and merge-extensible maps. Event JSDoc needs `@mode` and payload `@param`; scoped keys absent from payloads need `@dshScopeScan unsupported`. Public service methods document parameters and non-void returns.
@@ -114,7 +115,7 @@ Real-API tests and demos read `DEEPSEEK_API_KEY`, optional `DEEPSEEK_BASE_URL`,
 - **Testing policy** — [docs/testing.md](docs/testing.md). Every non-trivial model- or product-user-visible behavior change adds or updates a keyless snapshot through a real runnable example in the same PR; package tests, e2e-only assertions, and mock-only fixtures do not substitute for the assembled application transcript. Fixtures must replay on macOS/Linux; fix fixtures, not normalizers.
 - **A tool's UI render intent is part of its design**, decided up front (`generic`/`terminal`/`diff`, `locations`); presentation methods are pure functions of `args` ([cookbook](docs/cookbook/adding-a-tool.md)).
 - **Plan unit, e2e, and snapshot coverage** for new seams, lifecycle shapes, and transcript surfaces; missing snapshot-harness support is part of the implementation, not deferred follow-up.
-- **Use incremental merge commits.** Split independent changes; never squash, rebase, or rewrite pushed history. Fix the introducing PR before merging down-stack. If the base advances mid-merge, never restart: finish the checkpoint, push when authorized, then merge the newer tip separately ([rationale](.agents/notes/implemented/process/2026-07-26-incremental-pr-base-retargeting.md)).
+- **Use incremental merge commits.** Split independent changes. Pushed history may be rewritten before review; afterward prefer new commits. Fix the introducing PR before merging down-stack. If the base advances mid-merge, finish the checkpoint, push when authorized, then merge the newer tip separately ([rationale](.agents/notes/implemented/process/2026-07-26-incremental-pr-base-retargeting.md)).
 - **Label PRs:** one kind (`feature`/`bug-fix`/`doc`/`testing`/`cleanup`), each matching area; the [taxonomy](.agents/notes/implemented/process/2026-07-25-semantic-pr-label-taxonomy.md) is extensible.
 - TODO markers: `FIXME`/`TODO`/`XXX` by urgency ([semantics](docs/development.md)).
 - Files end with exactly one trailing newline; `git diff --cached --check` (pre-commit) gates it.