fix(tea-plugin): surface a one-time session-cost notice at plugin activation

[gmoncor]

What: Add a one-time, non-blocking stderr notice inside TeaPlugin.validate() stating that enabling tea's six true-by-default settings injects 6 extra agent sessions per story, pointing to docs/tea-plugin-guide.md.

Why: The six cost-affecting settings all default to true with no signal at the moment of activation; the guide documents the cost but an operator who edits policy.toml or toggles the plugin without reading it first gets no in-the-moment warning.

How:

• Add the stderr notice to TeaPlugin.validate(), reusing the existing PluginError/stderr-notice call site.
• Do not change any of the six defaults, this is a visibility fix, not a default change.

Testing: Add a test to tests/test_plugin_tea.py asserting the notice is emitted on validate() when the defaults are in effect, and that the plugin still activates normally.

Changelog: "Added: the TEA plugin now prints a one-time notice at activation about the extra agent sessions its default settings add per story."

🤖 Generated with Claude Code

[coderabbitai]

Important

Draft PR not reviewed

Draft PRs are not automatically reviewed by default.

• Trigger a manual review

To automatically review draft PRs, update your CodeRabbit configuration:

reviews:
  auto_review:
    drafts: true

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}