CONFIG_PATH resolved to ROOT_DIR/config.json (/app/config.json in Docker), but only
DATA_DIR (/app/data) is the mounted volume — every other artifact (DB, cookies, logs,
avatars) already lives under DATA_DIR. So on first run the default config was written
into the ephemeral image layer (never appearing in the volume), and a manually-placed
data/config.json was ignored because the bot read/wrote the root path.
- Move CONFIG_PATH to DATA_DIR/config.json so it lands in the volume and manual edits
take effect.
- Add migrateLegacyConfig(): one-time move of an existing root-level config.json into
the data dir, so existing local installs keep their settings (no silent reset).
- Tests for first-run persistence + the three migration cases.
- README directory tree updated to data/config.json.
Fixes#86
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
