Bump workspace version 0.4.6 -> 0.4.7 and ship the bug fix flagged by Devin
on PR #18: an uncommented `DEEPSEEK_API_KEY=` line in .env.example caused
`cp .env.example .env` to load an empty key, which `apply_env_overrides`
then propagated into the config and `Config::validate()` rejected on
startup with "api_key cannot be empty string".
- .env.example: comment out the empty `DEEPSEEK_API_KEY=` placeholder.
- crates/tui/src/config.rs: skip empty `DEEPSEEK_API_KEY` env values in
`apply_env_overrides`, matching the facade's empty-string filter.
- Add `apply_env_overrides_ignores_empty_api_key` regression test.
- Bump Cargo.toml workspace version, npm wrapper version + binary version,
and Cargo.lock.
Hunter Bown