Added ability to select bytecode invalidation mode of generated .pyc

[wimglenn]

Since Python 3.7, deterministic pycs are possible (see PEP 552)
To select the bytecode invalidation mode explicitly by env var:

PYC_INVALIDATION_MODE=UNCHECKED_HASH uv pip install --compile ...

Valid values are TIMESTAMP (default), CHECKED_HASH, and UNCHECKED_HASH.
The latter options are useful for reproducible builds.

[konstin]

Thanks!

I added specific error handling and a test and fixed a bug the error handling surfaced.

$ PYC_INVALIDATION_MODE=bogus cargo run -q pip install --compile django
Resolved 3 packages in 4ms
Installed 3 packages in 45ms
error: Failed to bytecode compile /home/konsti/projects/uv/.venv/lib/python3.12/site-packages
  Caused by: Python process stderr:
Invalid value for PYC_INVALIDATION_MODE "bogus", valid are "TIMESTAMP", "CHECKED_HASH", "UNCHECKED_HASH":
  Caused by: Bytecode compilation failed, expected "/home/konsti/projects/uv/.venv/lib/python3.12/site-packages/asgiref/sync.py", received: ""

@charliermarsh and/or @zanieb: Do we have a good spot to document advanced non-cli configuration such as PYC_INVALIDATION_MODE?

[konstin]

(Sorry for the CI failures, it's passing locally for me)

[zanieb]

@konstin I'd just add a "Compilation of Python modules" section to the "Advanced Usage" part of the README and explain --compile and this environment variable.

[konstin]

Made a separate issue for: #2303