Add mypy to CI in warn-only mode

[RBhupi]

Area

Acquisition — data download or queuing

Motivation

Science — needed for a research or analysis workflow

Problem

Scope

Introduce static type checking without blocking merges.

Proposed solution

Tasks

• Enable mypy in CI
• Configure non-strict mode
• Allow missing stubs for now (pandas, scipy, etc.)
• Do not fail CI on errors initially
• Log errors for tracking

Done

• mypy runs in CI and reports issues without blocking

Alternatives considered

No response

Additional context

No response

Checklist

• I searched existing issues and this has not been requested before
• This is one focused request, not multiple features bundled together