🐛 FIX: Windows pytest fails on backslash in TOML basic string

[ubmarco]

Summary

• tests/test_config.py::TestLoadMountsFromToml::test_absolute_paths_pass_through_unchanged interpolated a Windows tmp_path (C:\Users\runneradmin\AppData\Local\…) into a TOML basic string. The TOML parser sees \U and tries to read 8 hex digits for a \Uxxxxxxxx escape, finds sers…, and raises Invalid hex value (at line 2, column 12) before load_mounts_from_toml returns.
• Fix: switch the two interpolated values to TOML literal strings (single quotes), where backslashes are taken verbatim. The round-trip assertion still holds — literal strings preserve their content byte-for-byte, so the absolute path the test wrote equals what the loader gives back.
• Unblocks the Windows pytest cell of ci.yml, currently red on main and on build(deps): bump astral-sh/setup-uv from 6 to 7 #1 (dependabot setup-uv 6→7). build(deps): bump astral-sh/setup-uv from 6 to 7 #1 only surfaces this pre-existing test bug; it did not cause it.

Failure on main (run 26251744910)

src = '[[mounts]]\ndir = "C:\\Users\\runneradmin\\AppData\\Local\\Temp\\…\\abs"\nmount_at = "_g/abs"\n'
pos = 22, hex_len = 8
E   tomllib.TOMLDecodeError: Invalid hex value (at line 2, column 12)

Test plan

• uv run pytest tests/test_config.py -q (Linux) — 58 passed
• uv run --frozen prek run --all-files — all hooks pass
• CI Windows pytest cell goes green on this PR
• Rebase / re-run of build(deps): bump astral-sh/setup-uv from 6 to 7 #1 against new main after merge → all green