The root_path for dynaconf resolved to site-packages instead of the
application root when installed non-editable (Docker). This caused all
settings without env var overrides to be None, crashing on startup with
a TypeError in chunk size validation.
Fix root_path to fall back to CWD when settings.toml isn't at the
source-tree path, and refactor get_settings() to only pass values
dynaconf actually has — letting Settings dataclass defaults apply for
unconfigured keys. Mount settings.toml into all docker-compose MCP
services as a read-only volume.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
