ci: add GitHub workflow for publishing dev releases

[christian-bromann]

This PR adds a new GitHub Actions workflow that enables maintainers to publish dev releases of individual packages for testing purposes.

What's New

Dev Release Workflow (.github/workflows/dev-release.yml)

A manually-triggered workflow that allows publishing pre-release versions of any package in the monorepo.

Features:

• 📦 Package Selection - Choose from all available packages (langchain, @langchain/core, @langchain/openai, etc.)
• 🌿 Branch Selection - Publish from any branch, not just main
• 🏷️ Customizable NPM Tag - Defaults to dev, but can be changed (e.g., beta, next, canary)
• 🔖 Version with Git SHA - Versions include the commit SHA for traceability (e.g., 1.1.0-dev.abc1234)

[changeset-bot]

⚠️ No Changeset found

Latest commit: 48743e7

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

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