
Copilot rail can pick which Snowflake connections TOML to use.

### Added

- Copilot rail **Config file** + **Connection** selectboxes on one row — the connection popover lists `~/.snowflake/*.toml`. A single file is still listed (one option). `toml_file=` sets the default. Profile names come from the selected file. Helpers: `list_snowflake_connections()`, `list_snowflake_toml_files()`, `resolve_snowflake_config_path()`.

