Plan: Release Varbase Podcasts Base 2.0.0

Problem/Motivation

Release Varbase Podcasts Base 2.0.0, a new major and a stable release.

• Why a new major: the show and episode model has no upgrade path for existing podcast nodes, and The Rightup 1.0.0 requires ~1.0.0, so shipping it as 1.0.1 would break fresh Rightup 1.0.0 installs.
• Why stable, not alpha: composer create-project drupal/cms sets no minimum-stability, so an alpha could never be installed through the Drupal CMS installer.

Proposed resolution

• Set the version to 2.0.0 on the 2.0.x branch, pin the cross-dependencies (~4.0.0, ~1.0.0), update the README badge, CHANGELOG and AGENTS.md.
• Consumers move to "drupal/varbase_podcasts_base": "~2.0.0". The Rightup moves to it in its next release.
• Do not release from 1.0.x again: it now carries the breaking change.

Remaining tasks

• ✅ File an issue
• ✅ Release MR (!16)
• ✅ Tag 2.0.0
• ✅ Release node
• ✅ Close the released issues
• ❌ Back to DEV
• ❌ Reviewed by a human
• ❌ Code review by maintainers
• ❌ Full testing and approval
• ❌ Credit contributors
• ❌ Review with the product owner
• ✅ Update Release Notes
• ✅ Release (2.0.0)

User interface changes

• N/A

API changes

• N/A

Data model changes

• The show and episode model from #3622954. No upgrade path from 1.0.x.

Release notes snippet

• #3622954: A podcast is a show with episodes: add the Podcast episode content type and the views that list both
• #3627732: Editors can add Listen on links to an episode; the podcast's links show when it has none

AI-Generated: Yes