[Feature]: Publish GitHub Releases to enable release notifications and subscriptions

### Problem or opportunity

Developers and platform teams using twg-cli need a standard, low-friction way to stay informed when new versions or critical updates are published.

Currently, atlassian/twg-cli has no GitHub Releases or git tags created, even though docs/release-integration.md outlines a step for creating GitHub Releases and specifies that releases should contain adoption-focused release notes and links. Because no GitHub Releases are published on this repository, users cannot take advantage of GitHub's native repository watch/subscription mechanism (Watch -> Custom -> Releases) to receive notifications (via email, web notifications, or webhooks/automation) when a new release is cut.

### Proposed outcome

Publish official GitHub Releases (and corresponding git tags) on atlassian/twg-cli alongside new versions:

- GitHub Native Notifications: Developers can select Watch -> Releases on atlassian/twg-cli to automatically receive email and web notifications when new versions drop.
- Adoption-Oriented Release Notes: Include the summary of changes, install/update instructions (twg update), and relevant plugin/skill notes as outlined in docs/release-integration.md.
- Automation & Tooling Support: Enables CI/CD pipelines, Dependabot/Renovate, or custom agent monitors that poll GitHub Releases via the standard GitHub REST/GraphQL APIs.

### Area

Release communication

### Current workaround

- Manually polling https://teamwork-graph.atlassian.com/cli/manifest.json or https://teamwork-graph.atlassian.com/cli/CHANGELOG.md.
- Manually running twg update or checking twg --version periodically.
- Watching all repo activity (commits/PRs), which introduces excessive noise for users who only care about stable version releases.

Start with docs/release-integration.md, then inspect the current manifest.json and CHANGELOG.md release process. Define how new versions will produce GitHub Releases and corresponding git tags, with adoption-focused notes, twg update instructions, and plugin or skill details; done means users can subscribe to official release notifications.

Written by the indexing model from the issue text.