DaemonConfig.from_env() now best-effort loads a .env file (find_dotenv
usecwd, load_dotenv override=False) so operators can manage daemon env
vars via .env, with real OS env taking precedence. Add python-dotenv
dependency, gitignore .env, ship .env.example, and add config tests
(load / OS-env precedence / absence regression / missing-DSN guard).
Verification: 78 passed, ruff clean, .env ignored + .env.example tracked,
and a .env-only DaemonConfig smoke. Processed via the minor-change fast
path: REQ-010 (Configuration) -> Implemented, BAT-003 (batch-lite,
no design) -> release-candidate.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
