distcheck: vestigial CLI-binary prerequisite left behind by #738 (skipped integration test, dead CI step, stale README) #972

Found while investigating #961 (closed as not planned). Three artifacts of the same change: #738 dropped dirsql/_binary/ so the wheel's extension module carries the CLI in-process, but the cargo-built dirsql binary is still treated as a prerequisite in three places. One of them silently skips a test.

Problem

python_flow/gate.py records that the prerequisite is gone:

- No binary staging since #738: the wheel's extension module carries the CLI
  and the console script calls it in-process, so there is nothing to stage

Confirmed: gate.py never references a binary or target/ anywhere outside that docstring caveat. But:

1. tests/integration/python_flow_test.py skips itself on a prerequisite the flow no longer has. Lines 23–32 locate target/{release,debug}/dirsql and pytest.skip("dirsql CLI binary not built ...") when it is absent. binary is never used again — it is not passed to run(), which takes (_PKG, _REPO). So the test skips whenever no cargo binary happens to be lying around, even though it would pass. This is the one with teeth: a green run where the case never executed.

2. dirsql-python-ci.yml's distcheck job builds a binary nothing consumes. The Build dirsql CLI binary step (cargo build -p dirsql --features cli) runs on every Python PR reaching that job and feeds nothing. The Install Rust / Rust cache steps stay — maturin build compiles the PyO3 extension.

3. internals/distcheck/README.md:29 still says the python flow "stages the cargo-built dirsql binary under dirsql/_binary/".

Also stale in the same README (unrelated cause, #942)

• :54 — gated by conventions.yml's internals-distcheck job → internals-distcheck-ci.yml
• :67 — "the CI distcheck jobs (python-test.yml / ts-test.yml)" → both files were deleted in the ci: run only the checks relevant to the changed paths #942 consolidation

Change

1. Drop the binary lookup and its pytest.skip from python_flow_test.py, keeping the maturin guard. Confirm the test then runs (and passes) with no cargo binary present — that is the fix's whole point, so it wants observing rather than assuming.
2. Delete the Build dirsql CLI binary step from dirsql-python-ci.yml's distcheck job.
3. Correct the three README lines.

Validation

(1) is a real behavior change to a test tier and needs its skip-to-run transition observed directly. (2) is verified by the Packaging distcheck (python) job staying green without the step — that job runs on any PR touching packages/python, and this issue's PR will touch dirsql-python-ci.yml, which is in its own paths:. (3) is docs.

Note the node flow is unaffected: it genuinely needs the staged host CLI under packages/ts/build/<triple>/, which is why node_flow_test.py's skip guard is still correct.