Add docs/developer-testing-guidelines.md covering test commands, targeted
runs, syntax/diff checks, adding MCP tool tests, safe API/auth mocking,
profile/allowed-operation gate tests, self-review/self-merge gate tests,
no-secret regression expectations, unit vs future Docker integration tests,
and read-only vs mutating tool expectations. Link it from the README Tests
section and note the suite table is non-exhaustive.
Documentation only; no code behavior changed.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
sysadmin