Log enabled preview features
For https://github.com/astral-sh/uv/issues/17964 / https://github.com/astral-sh/uv/pull/17965. Logging now gets initialized earlier to cover more of the startup procedure.
Also decrease the log level for lock acquisition from debug to trace, that happy path usually isn't relevant.
```
$ cargo run -q pip install tqdm -v
DEBUG uv 0.10.2+7 (cc6e7a600 2026-02-11)
DEBUG Searching for default Python interpreter in virtual environments
DEBUG Found `cpython-3.14.0-linux-x86_64-gnu` at `/home/konsti/projects/uv/.venv/bin/python3` (virtual environment)
DEBUG Using Python 3.14.0 environment at: .venv
DEBUG Requirement satisfied: tqdm
Audited 1 package in 2ms
```
```
$ cargo run -q pip install tqdm -v --preview
DEBUG uv 0.10.2+7 (cc6e7a600 2026-02-11)
DEBUG Preview is enabled
DEBUG Searching for default Python interpreter in virtual environments
DEBUG Found `cpython-3.14.0-linux-x86_64-gnu` at `/home/konsti/projects/uv/.venv/bin/python3` (virtual environment)
DEBUG Using Python 3.14.0 environment at: .venv
DEBUG Requirement satisfied: tqdm
Audited 1 package in 2ms
```
```
$ cargo run -q pip install tqdm -v --preview-features target-workspace-discovery
DEBUG uv 0.10.2+7 (cc6e7a600 2026-02-11)
DEBUG Enabled preview features: target-workspace-discovery
DEBUG Searching for default Python interpreter in virtual environments
DEBUG Found `cpython-3.14.0-linux-x86_64-gnu` at `/home/konsti/projects/uv/.venv/bin/python3` (virtual environment)
DEBUG Using Python 3.14.0 environment at: .venv
DEBUG Requirement satisfied: tqdm
Audited 1 package in 1ms
```
