Setuptools 69.0.2 on Windows emits `wheel/./project` instead of
`wheel/project` in bdist install paths. Add a test filter to normalize
redundant `/./` path components so the snapshot matches on all platforms.

The raw setuptools output on Windows uses backslashes (`wheel\.\.\project`),
so the filter needs `[\\/]\.[\\/]` to match both slash directions, not
just forward slashes.

Move the CI dev drive layout from `D:\uv` + `D:\uv-tmp` to
`D:\uv\repo` + `D:\uv\tmp` so the workspace path is never a prefix
of the temp dir. This removes the need for the fragile `insert_pos`
logic in `with_filtered_system_tmp` that searched for `[TEMP_DIR]/`
by replacement string value to maintain filter ordering.

…oc comment

Move the many pip-specific filters (temp dirs, progress bars, hashes,
sizes, platform tags, etc.) into a reusable `with_filtered_pip_output`
method on `TestContext`. Also trim the `with_filtered_system_tmp` doc
comment to remove unnecessary implementation details.

Instead of snapshotting the entire verbose pip install output (which is
noisy and fragile across platforms), extract just the FOUND_UV= lines
and snapshot those. This removes the need for with_filtered_pip_output
and all the pip-specific filters.

… assert on missing output

- Remove superfluous .clone() by binding the assert result
- Only search stderr for FOUND_UV= (that's where setup.py prints it)
- Use insta::with_settings! with filters instead of manual apply_filters
- Assert FOUND_UV= lines are non-empty with full stderr for debugging

- Replace `.map(|line| line.trim())` with `.map(str::trim)`
- Use `apply_filters` instead of `insta::with_settings` to avoid
  `String`-to-`&str` tuple coercion issues with unstable `str_as_str`