upgrade uv.lock

[lilly-luo]

• uv run ucode claude works
• uv run ucode codex works

when testing codex app server, i ran into a problem where ucode codex app worked with uv run but not when i actually installed the new ucode. this was because uv run was using uv.lock which had toml at 0.14 but when users actually instead ucode, they get toml 0.15.1 (on which ucode codex app is broken).

this PR:

1. updates uv.lock
2. makes the necessary changes for mcp to match the new versions

[sunishsheth2009]

Reviewed the code and verified the proxy against the new lock (checked out lilly/upgrade-uv-lock, uv sync --frozen, ran the suite). Summary:

✅ Proxy verified working on the new lock. uv sync --frozen resolves mcp 2.1.1 / httpx2 2.12.0 / anyio 4.14.2; tests/test_mcp_proxy.py is 29/29 green and ty is clean. The mcp_proxy.py change is annotation-only — concrete MemoryObjectReceiveStream/MemoryObjectSendStream types swapped for structural _ReceiveStream/_SendStream Protocols, and _pump/_pump_upstream made generic. The function bodies are unchanged, so runtime behavior is identical. Sensible decoupling from the concrete anyio stream types (which is what lets the same code path work under both mcp majors).

🔴 Description item 3 ("excludes gpt-5-6- astra from tests") is not in this PR. The diff touches only cli.py, mcp_proxy.py, and uv.lock — no test file. The astra-skip logic (test_astra_is_skipped, test_web_search_skips_astra, the "astra" frozenset in tests/test_e2e.py) already exists on main; this PR adds nothing to it. So either the description is stale and should drop item 3, or a commit was dropped and needs pushing. Please reconcile — approving off the description would approve something that isn't here.

One inline note on the unrelated cli.py change below.