Set opt-level 1 for fast build profile (#16481)
Test cases:
```
touch crates/uv-resolver/src/resolver/mod.rs && time cargo nextest run --cargo-profile dev --no-fail-fast -- --skip python_install
touch crates/uv-resolver/src/resolver/mod.rs && time cargo nextest run --cargo-profile fast-build --no-fail-fast -- --skip python_install
```
On my machine, we go from 7.x s (dev) to 8.x s (dev + opt-level 1) for
compilation, and 6.x s for the combined `fast-build` profile. With
opt-level 1, we go from 84s for the first line to 64s for the second
line.
