fix(ci): refresh lockfile package sources

[pi-dal]

Which issue or RFC does this PR close?

Related to #1309.

Rationale for this change

The OceanBase acceptance workflow failed before running its scenarios because the frozen lockfile referenced a pydantic-core wheel on the Tsinghua PyPI mirror that returns HTTP 403.

What changes are included in this PR?

• Refresh uv.lock against the official PyPI default index.
• Replace the mirror-specific registry and distribution URLs with official PyPI URLs.
• Preserve the resolved package versions and dependency graph.

Are there any user-facing changes?

No API or runtime behavior changes. Builds and installations no longer depend on the unavailable mirror URL recorded in the lockfile.

How was this change tested?

• mise exec -- make check
• mise exec -- uv run python -m pytest --doctest-modules -q — 626 passed, 13 skipped
• Verified the previously failing Linux x86_64 pydantic-core wheel URL from the refreshed lockfile returns HTTP 200.

Docker is unavailable in the local environment, so the container acceptance build will be verified by CI.

AI usage statement

Built with Codex (GPT-5).

[pi-dal]

Context for review: this is a reliability hardening, not a deterministic behavioral or dependency-version regression.

The trigger was #1309: its OceanBase acceptance job ran in westus3 and received HTTP 403 for the locked pydantic-core wheel from the Tsinghua PyPI mirror before scenarios began. A later #1311 job, still using the pre-change lockfile, freshly downloaded the same package successfully from centralus. The mirror is therefore region/IP-dependent.

This PR removes those hard mirror URLs in favor of official PyPI URLs so builds do not depend on that availability difference. All checks are green, including SQLite and OceanBase acceptance.

Evidence: failed job https://github.com/oceanbase/powercontext/actions/runs/32486415491/job/96784021364; successful later download https://github.com/oceanbase/powercontext/actions/runs/32507898779/job/96852286657.