Harness-agnostic entry point: read by any agent harness that loads AGENTS.md
(kilo, opencode, Claude, Cursor, ...).
A non-test change under tinyagentos/ or desktop/src/ requires a
changelog.d/<pr>-<slug>.md fragment (or a CHANGELOG.md line) in the same
PR. The single-source rule lives in docs/changelog-fragments.md
and is summarized in CONTRIBUTING.md (the "Documentation gate" section).