chore: release 0.2.0

[c1-squire-dev]

Summary

• Use release-plz set-version to prepare agent-tui 0.2.0
• Update the agent-tui package version and changelog heading to 0.2.0

Notes

• This is the release-plz-supported exact-version path, rather than a release-please Release-As commit.
• If 0.2.0 is the desired release, this supersedes the generated 0.1.13 release PR (chore(agent-tui): release v0.2.1 #122).

Verification

• release-plz set-version agent-tui@0.2.0
• cargo metadata --no-deps --format-version 1 reports agent-tui version 0.2.0
• git diff --check