chore: release as 0.4.0 (sandbox/testnet preview)

[lexaisnotdead]

Ship the rewritten SDK as 0.4.0, not 1.0.0 — the product is testnet-only and pre-external-audit, so a 1.0.0 would overstate maturity and lock semver stability before the API surface is frozen.

• Version → 0.4.0 in package.json, pyproject.toml, __init__.py (continues cleanly past the old npm 0.3.0; advances latest while staying 0.x = "may change").
• Sandbox/testnet notice added to the root + TypeScript + Python READMEs.
• PyPI Development Status :: 4 - Beta classifier (+ audience/topic classifiers).
• Cut 1.0.0 at the mainnet + external-audit gate.

Both packages verified to build at 0.4.0 (TS dist + Python wheel/sdist).

🤖 Generated with Claude Code

Summary by CodeRabbit

• Documentation

  • Added prominent notices clarifying that the SDK is a sandbox/testnet preview and defaults to a development environment.
  • Warned that APIs may change before the stable 1.0 release and should not be used with mainnet funds.

• Chores

  • Updated the Python and TypeScript package versions to 0.4.0.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 7d24b9a2-179e-4947-8080-a6632a4c8f34

📥 Commits

Reviewing files that changed from the base of the PR and between 7396e2b and a2e4901.

📒 Files selected for processing (6)

• README.md
• python/README.md
• python/hashlock/__init__.py
• python/pyproject.toml
• typescript/README.md
• typescript/package.json

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📝 Walkthrough

Walkthrough

The SDK version is updated to 0.4.0 for Python and TypeScript packages. Root and language-specific READMEs now identify the SDK as a sandbox/testnet preview and warn against using mainnet funds.

Changes

SDK release updates

Layer / File(s)	Summary
Package version metadata python/hashlock/__init__.py, python/pyproject.toml, typescript/package.json	Python and TypeScript package versions change from 1.0.0 to 0.4.0.
Sandbox preview documentation README.md, python/README.md, typescript/README.md	Documentation describes the sandbox endpoint, testnet-only scope, possible pre-1.0 API changes, and restriction against mainnet funds.

Estimated code review effort: 1 (Trivial) | ~5 minutes

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly summarizes the version release to 0.4.0 and the sandbox/testnet preview intent.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch chore/v0.4.0-beta

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