Include setup.py in CI venv and Rust extension cache keys

[TheJulianJES]

Since #128, the Rust extension is defined in setup.py instead of pyproject.toml. This adds setup.py to the CI cache keys, so changing it invalidates the cached venvs and Rust extension builds.

Changes

• Add setup.py to all base venv cache keys (all jobs restoring the venv use the same key).
• Add setup.py to the macOS/Windows Rust extension cache keys.

Detailed AI-generated PR description

Verbose AI-generated PR description (CLICK TO EXPAND)

The base venv cache key hashes pyproject.toml, Cargo.toml, Cargo.lock and src/**, and the macOS/Windows Rust extension cache key hashes the Cargo files and src/**. Before #128, the extension was configured through [tool.setuptools-rust] in pyproject.toml, so a change to it invalidated the cached venvs. #128 moved the RustExtension(...) definition (and the platform check deciding whether to build it) into setup.py, which isn't part of either key. A future change there, e.g. to the extension's arguments or the platform check, would then be served stale cached venvs and extension builds on macOS/Windows.

This adds setup.py to:

• the base venv key in all 8 places that build or restore it (prepare-base, prek, pytest, pytest-esphome, pytest-macos, pytest-windows, pytest-serialx-compat, coverage). They have to stay identical, since most jobs restore with fail-on-cache-miss: true.
• the Rust extension key of the macOS and Windows test jobs.

No other cache keys depend on setup.py (prek, ESPHome daemon, CP2102 emulator, cp210x modules, ser2net, Pyodide).

As the keys change, this PR's CI rebuilds all venvs once.

Related:

• Follow-up to Restrict Rust extension builds to Windows and macOS #128
• A stacked follow-up PR removes the now-unused Rust build dependencies from Linux CI

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 94.31%. Comparing base (7334430) to head (147d3b6).

Additional details and impacted files

@@           Coverage Diff           @@
##              dev     #134   +/-   ##
=======================================
  Coverage   94.31%   94.31%           
=======================================
  Files          25       25           
  Lines        4345     4345           
=======================================
  Hits         4098     4098           
  Misses        247      247           

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