ci: speed up Python checks by running ruff/mypy without waiting for setup

[raman325]

Proposed change

Removes the needs: setup dependency from the ruff and mypy jobs so they start immediately in parallel with setup, instead of waiting ~30s for the version matrix computation they don't need.

Also:

• Merge CI-only pip installs (pytest-cov, pytest-github-actions-annotate-failures) into the main install step
• Optimize apt-get with --no-install-recommends

Before: setup → (ruff | mypy | pytest) — ruff/mypy waited for setup
After: (ruff | mypy | setup) → pytest — ruff/mypy start immediately

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New feature (which adds functionality)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue:
• This PR is related to issue:

[Copilot]

Pull request overview

This PR optimizes the Python CI workflow by allowing static analysis jobs to start immediately (in parallel with the version-matrix setup job), reducing overall wall-clock time for checks.

Changes:

• Removed the needs: setup dependency from the ruff and mypy jobs and switched them to use env.TARGET_PYTHON.
• Consolidated CI-only Python test dependencies into the main dependency install step.
• Streamlined system package installation with apt-get install -y --no-install-recommends.

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.66%. Comparing base (9b9f49c) to head (3967917).
⚠️ Report is 1 commits behind head on main.
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1078   +/-   ##
=======================================
  Coverage   95.66%   95.66%           
=======================================
  Files          46       46           
  Lines        5279     5279           
  Branches      503      503           
=======================================
  Hits         5050     5050           
  Misses        229      229           

Flag	Coverage Δ
python	97.32% <ø> (ø)

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