chore(ruff): the acceptance was whatever the default happened to be [skip-docs]

`uv sync --frozen` resolved ruff 0.15.22 and the tree read clean. A loose
install resolves 0.16.6, under which the SAME untouched code reports 148
findings -- 4 more than round 9 counted, because this round added four files.
All of them are new rules rather than new defects: 0.16 widened the default
rule set to whole families (YTT, ASYNC, PL, ISC, C4, UP, B, SIM, FURB, ...).

(`[skip-docs]` is for CLAUDE.md, which a lint-configuration change does not
reach. README's developer section IS updated in this commit.)

THE DEFECT IS NOT THE 148, IT IS THAT NOBODY CHOSE THEM. `[tool.ruff]` set only
`line-length` and `target-version`, so the acceptance was ruff's default, and
the tree stayed green only as long as the lockfile froze an old ruff. `select`
is now written down: `E4`, `E7`, `E9`, `F` (the historical default), `I`
because this tree already keeps imports sorted, and `RUF100` so a `noqa` that
has stopped meaning anything is caught rather than left as decoration. Pin
`ruff>=0.9` -> `ruff>=0.16.6,<0.17`.

Per rule, before -> after: RUF100 50 -> 0, I001 20 -> 0, ISC004 19, PLW1510 8,
C408 8, EXE001 6, RUF007 5, PLE2515 4, UP031 3, B017 3, and fourteen more with
2 or fewer -- the families out of the declared set are 0 by selection, and 148
is the number to start from if they are adopted, which is a separate decision
and not one to take inside a version-pin commit. 57 were auto-fixed; one E402
was reintroduced by the import-sorting fix merging a block away from its
`noqa`, and got the directive back rather than a bare one.

`S` IS MEASURED OUT, NOT ASSUMED OUT: it reports 2657 `S101` on a suite whose
every assertion is an `assert`, and `S603` flags 19 subprocess calls of which
one was ever marked -- selecting it buys 18 suppressions and no defect. Two
`noqa` directives naming non-selected rules were dropped with that reason
recorded in the configuration instead.

THE TWO FILES 0.16 WOULD REFORMAT ARE MARKDOWN, NOT PYTHON: `README.md` and
`docs/2026-09-08-blindsone-below-k-k2.md`. 0.16 formats fenced Python inside
markdown, and both blocks are RECORDS -- the second is a quotation of
`COST_VOCABULARY` as it stood when that measurement was taken. Reformatting a
quotation makes it stop being one, so markdown is excluded from the formatter
and `ruff format --check .` stays in the acceptance over `.py`.

`tools/okf_consume_measure.py` is fenced by the order as run-not-edited, so its
three findings are exempted by path with the reason and the debt named, and its
bytes are untouched.

THE LOCKFILE TRAP IS CLOSED, NOT AVOIDED. `uv.lock` predated the `[ocr]` extra,
so any unlocked resolve wrote that extra's transitive tree back into it -- 681
insertions over 4 deletions, twice now, and round 9 recorded the cause as
`uv run` OUTSIDE the project when it is `uv run` without `--frozen` INSIDE it.
The relock is complete for every declared extra (703 insertions, 26 deletions),
and measured after it, an unfrozen `uv run` leaves the file alone.

`ruff check src tests tools`, `ruff format --check .` (0.16.6), `mypy src` over
21 files and 1535 tests, all green.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

pyproject.toml

@@ -119,7 +119,12 @@ extract = ["pdfplumber>=0.11.10,<0.12", "pypandoc-binary==1.17"]
 ocr = ["rapidocr>=3.9,<4", "onnxruntime>=1.20,<2", "pypdfium2>=4,<6"]
 
 [dependency-groups]
-dev = ["pytest>=8", "mypy>=1.14", "ruff>=0.9"]
+# ruff PINNED TO A RANGE, not floored at an ancient version. `ruff>=0.9` let
+# the lockfile decide which ruff ran, and a frozen 0.15.22 is what made this
+# tree read green while 0.16.6 found 148 things in it. The floor is now the
+# version the acceptance was measured under, and the ceiling is the next minor,
+# because 0.16 is itself the release that widened the default rule set.
+dev = ["pytest>=8", "mypy>=1.14", "ruff>=0.16.6,<0.17"]
 
 [tool.hatch.build.targets.wheel]
 packages = ["src/llm_ingestion_okf"]
@@ -141,6 +146,55 @@ packages = ["src/llm_ingestion_okf"]
 line-length = 100
 target-version = "py310"
 
+# THE RULE SET IS DECLARED, and that is the whole repair rather than a
+# preference. Until 2026-09-09 this table set only `line-length` and
+# `target-version`, so the ACCEPTANCE was whatever ruff's default happened to
+# be -- and the tree read green only because `uv.lock` froze ruff at 0.15.22.
+# Upgrading to 0.16.6 turned up 148 findings in code nobody had touched, all of
+# them new rules rather than new defects: 0.16 widened the default set to
+# include whole families (YTT, ASYNC, PL, ISC, C4, UP, B, SIM, FURB, ...). An
+# undeclared `select` means every ruff release silently redefines what "clean"
+# means, which is exactly how a formatter gate went red unseen.
+#
+# WHAT IS HERE AND WHY. The historical default (`E4`, `E7`, `E9`, `F`), plus
+# `I` because this tree already keeps its imports sorted, plus `RUF100` so a
+# `noqa` that has stopped meaning anything is caught rather than left as
+# decoration.
+#
+# WHAT IS NOT HERE, MEASURED RATHER THAN ASSUMED. `S` (bandit) reports **2657**
+# `S101` on a test suite whose every assertion is an `assert`, and `S603`
+# reports **19** subprocess calls of which one was ever marked -- selecting it
+# would buy 18 new suppressions and no defect. The remaining families the 0.16
+# default adds are a real question and a separate one: they are worth adopting
+# deliberately, not inside a version-pin commit, and the number to start from
+# is the 148 above.
+[tool.ruff.lint]
+select = ["E4", "E7", "E9", "F", "I", "RUF100"]
+
+# ONE FILE IS EXEMPT, and it is a fence rather than a judgement about the code.
+# `tools/okf_consume_measure.py` is a measurement instrument that published
+# figures were produced with, and the order that authorised this cleanup fenced
+# it explicitly: it is RUN, not edited, so its bytes stay as the numbers were
+# taken. Its three findings are a stale `noqa: E402` twice over and an import
+# order -- none of them a defect, all of them the same churn this upgrade
+# produced everywhere else, and all of them to be cleaned the next time the
+# fence is lifted. Named here rather than left to make the gate red for a
+# reason nobody could see.
+[tool.ruff.lint.per-file-ignores]
+"tools/okf_consume_measure.py" = ["I001", "RUF100"]
+
+# MARKDOWN IS NOT FORMATTED, and this is a decision the 0.16 upgrade forced.
+# ruff 0.16 formats fenced Python inside markdown. Two files here would change
+# under it, and both are RECORDS rather than source: `README.md`'s call example
+# and `docs/2026-09-08-blindsone-below-k-k2.md`'s QUOTATION of `COST_VOCABULARY`
+# as it stood when that measurement was taken. Reformatting a quotation makes it
+# stop being one, and this repository publishes reproduction blocks that a
+# reader is meant to be able to compare against what was run. The formatter's
+# job here is Python source; `ruff format --check .` is part of the acceptance
+# and stays so, over `.py`.
+[tool.ruff.format]
+exclude = ["*.md"]
+
 [tool.mypy]
 strict = true
 python_version = "3.10"