Bump jupyter-server to 2.18.0 and pin root_dir

[mishushakov]

Supersedes #274 (dependabot bump of jupyter-server 2.16.0 → 2.18.0).

The straight dependency bump breaks the sandbox: jupyter-server 2.18.0 ships path-traversal hardening (CVE-2026-35397) that rejects session creation when the contents root resolves to / — which is the cwd of the systemd-launched process (jupyter.service has no WorkingDirectory). Every POST /api/sessions then fails with <uuid> is outside root contents directory and the server never serves.

This PR carries the same bump plus pins c.ServerApp.root_dir = "/home/user" in template/jupyter_server_config.py so sessions are created relative to the execution cwd.

Changes

• Bump jupyter-server 2.16.0 → 2.18.0 (template/requirements.txt)
• Pin root_dir to /home/user (template/jupyter_server_config.py)

🤖 Generated with Claude Code

[cursor]

PR Summary

Medium Risk
Dependency upgrade plus a config fix on the Jupyter entrypoint; wrong root_dir would break all sessions, but the change is narrow and documented.

Overview
Upgrades jupyter-server from 2.16.0 to 2.18.0 and sets c.ServerApp.root_dir = "/home/user" in jupyter_server_config.py so sandbox session creation still works after 2.18.0’s path-traversal checks (CVE-2026-35397).

Without an explicit root, the server uses / as contents root under systemd (no WorkingDirectory), so relative session paths are rejected and POST /api/sessions fails. Pinning the root to /home/user aligns with where code runs.

Includes a patch changeset for @e2b/code-interpreter-template.

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[claude]

LGTM — straightforward dep bump with a well-justified root_dir pin to /home/user (the established sandbox cwd).

Extended reasoning...

Overview

This PR bumps jupyter-server from 2.16.0 to 2.18.0 in template/requirements.txt and adds c.ServerApp.root_dir = "/home/user" to template/jupyter_server_config.py. The PR description explains the motivation clearly: 2.18.0 ships path-traversal hardening (CVE-2026-35397) that rejects session creation when the contents root resolves to /, which is the cwd of the systemd-launched process. Without the explicit pin, every POST /api/sessions would fail.

Security risks

None of concern. The change moves in the safer direction by picking up upstream security hardening. The pinned root_dir of /home/user is the well-established sandbox working directory — it is the user owned via chown -R user:user /home/user in template/template.py, the default cwd in template/server/api/models/create_context.py, and the cwd used throughout template/server/main.py and the test suite (python/tests/*/test_cwd.py, js/tests/cwd.test.ts).

Level of scrutiny

Low. The changes total two small edits in template/build configuration. The root_dir value matches the existing convention everywhere else in the codebase, and the dependency bump is a minor version update carrying a security fix. The detailed inline comment makes the intent obvious to future readers.

Other factors

No bugs were found by the bug hunting system. The PR supersedes a dependabot bump (#274) and explains why the straight bump alone is insufficient. No outstanding reviewer comments require addressing.