Return the targeted pre-release pins installing version requires.
A stable deepagents-code release may mandate an exact pre-release
dependency (for example deepagents==0.7.0a7). This resolves those pins from
the release's PyPI metadata so command builders can pass them to uv as
first-party constraints — admitting only the named pre-release rather than
opting the whole resolution into pre-releases with a global --prerelease allow.
Note:
On any lookup failure (no requests, network/parse error) this returns
[] — "no pre-release admission". That is deliberately conservative
rather than fail-safe: the truly safe default would be to admit
pre-releases, but a spurious non-empty result would make
prerelease_upgrade_supported refuse the upgrade outright on non-uv
installs (Homebrew/other), regressing the common case. [] keeps those
installs upgradable; the cost is that, during a PyPI outage, a stable
release that genuinely pins a pre-release dependency may be installed
stable-only (and may then fail to resolve). Failures are logged at
warning so the blind decision is at least visible.
deepagents-code version to inspect.
Skip cached release metadata and fetch PyPI directly.
