bug(ci): pre-commit `uv run mypy` reports 96 a2a/protobuf errors that don't reproduce in .venv mypy

[bokelley]

Context

Every PR in the recent batch had to SKIP=mypy or --no-verify because uv run mypy src/adcp/ fails with 96 errors in client.py / protocols/a2a.py from a2a-sdk protobuf stubs. CI mypy passes cleanly. The hooks are bypassed routinely, defeating the point of having them.

Acceptance Criteria

• uv run mypy src/adcp/ reproduces clean locally (matches CI behavior)
• Pre-commit hooks no longer require routine bypass
• Solution is one of: pin a2a-sdk version, add type stubs, or exclude the affected files from mypy

Files

• .pre-commit-config.yaml
• pyproject.toml (mypy config)
• src/adcp/client.py
• src/adcp/protocols/a2a.py

[bokelley]

Triage

Classification: Bug
Bucket(s): No exact label match — tooling/CI (noted in run summary)
Status: drafting-pr
Milestone: omitted

What the experts said:

• code-reviewer: --extra dev is correct; activates [project.optional-dependencies] dev which contains types-protobuf; do not add ignore_missing_imports overrides (would suppress real errors)
• dx-expert: fix resolves the bypass habit; --extra dev works; nit that --group dev is more idiomatically uv since uv add --dev writes to [dependency-groups] — both work because types-protobuf is duplicated in both sections

My take: Root cause is that uv run mypy doesn't include optional extras by default, so types-protobuf stubs are absent and mypy flags every google.protobuf.* import. Adding --extra dev closes the gap with CI in one word. Draft PR #431 carries the fix.

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Triaged by Claude Code. Session: https://claude.ai/code/session_012s2eENfKoeaeeHUyV7Rd9y

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Generated by Claude Code