chore: sync pre-commit hook versions with uv.lock; make Instruments real enum members

[aradng]

• sync-with-uv keeps the pre-commit revs of ruff and mypy, and the mypy additional_dependencies marked # sync-with-uv, equal to the versions in uv.lock. mypy moves 1.19.1 → 2.3.0, ruff 0.15.7 → 0.15.21, and the pinned mypy deps to the locked pydantic, typing-extensions, mypy-extensions and types-pyyaml. returns isn't in uv.lock (only mypy's plugin uses it), so it stays unpinned.
• Instruments had no members. An Enum turns a function value into a method, so Instruments.REDIS was the bare function and list(Instruments) == []; instrument_otel only worked because it calls whatever it gets. mypy 2.3 flagged it. Each value is now enum.member(...); instrument_otel already uses .value for members. No service references Instruments directly. A test pins the members.
• tests/test_meta.py: the three reads through SelfSustaining's class forwarding get # type: ignore[misc], as the repo allows for that pattern.
• Version 0.5.8.

Verification: pytest 282 passed; prek run --all-files clean at mypy 2.3.0 and ruff 0.15.21; a second sync-with-uv run changes nothing.

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