Consolidate 6 distinct cache-key prefixes (v2-dependencies-,
v1-router-testing-deps-, v1-router-unit-deps-, v1-llm-translation-deps-,
v1-llm-responses-deps-, v3-litellm-uv-deps-, ui-e2e-py-deps-v2-) onto a
single v1-uv-cache-<uv.lock checksum> key shared across all Python jobs.
Cache only ~/.cache/uv (the content-addressed uv download cache,
hash-verified against uv.lock at install time). Drop ./.venv,
~/.local/{bin,lib}, and /home/circleci/.{pyenv,local} from cache paths.
~/.cache/uv is the only path uv sync needs to avoid re-downloading from
PyPI; everything else is rebuilt each run from that verified cache.
Remove partial-prefix restore-keys fallbacks — cache either hits exactly
on the uv.lock hash or rebuilds cleanly.
First run after merge will cold-miss on the new key; subsequent runs
hit the unified cache.
28e1d2f1a6