feat: add automated changesets release workflow

[draggie]

Closes #1388

Summary:

• Adds a Changesets-based release workflow with stable release PR/publish automation and manual canary releases.
• Uses npm trusted publishing/OIDC without npm publish tokens and disables package-manager caching in release jobs.
• Adds a temporary PR release dry-run job to preview status/snapshot version generation before publishing.

Validation:

• pnpm lint:ci
• pnpm typecheck
• pnpm test
• git diff --check

[vercel]

@draggie is attempting to deploy a commit to the Callstack Team on Vercel.

A member of the Team first needs to authorize it.

[changeset-bot]

⚠️ No Changeset found

Latest commit: ae2d85f

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.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

[dannyhw]

is --snapshot and --no-git-tag correct here? I don't see it on the docs:

Usage:
  $ changeset publish

Options:
  --otp <code>           One time password for npm publish 
  --tag <name>           Publish with the given npm dist-tag 
  --from-pack-dir <dir>  Publish from a packed output directory 
  --git-tag              Create a git tag for the release (default: true)

Examples:
  $ changeset publish --otp 123456
  $ changeset publish --tag beta

[draggie]

no-git-tag is fine, but snapshot is from different command not publish