fix(deps): lock watchfiles 1.x so the lock-based install works on Python 3.14

Loosening the specifier alone left uv.lock resolved to watchfiles 0.24.0, so
a uv sync/--frozen install from the lock on CPython 3.14 still fell back to
the failing source build. Upgrade the locked watchfiles to a 1.x release
that publishes cp314 wheels (uv lock --upgrade-package watchfiles).

Claude-Session: https://claude.ai/code/session_01HCVKnA7LeJZ44nxZz1uzF3

Author: michaelxu2288