[ADD] ruff: integrate Ruff as opt-in replacement for flake8, black, isort, autoflake and pyupgrade

[hbto]

# Description

Summary

Adds Ruff support to pre-commit-vauxoo via the existing
--compatibility-version / LINT_COMPATIBILITY_VERSION matrix system.
No behavioral change for existing consumers — Ruff is disabled by
default (position 8 = 10 in the current default string).

What changed

• pre_commit_vauxoo.py — adds ruff_matrix_value as position 8
  in TOOLS_ORDER. parse_matrix_compatibility() and copy_cfg_files()
  handle it automatically; no signature changes needed.

• cli.py — documents position 8 = Ruff in the
  --compatibility-version help text.

• cfg/ruff.toml.jinja (new) — Copier template rendered as
  ruff.toml in the target repo when ruff_matrix_value >= 20.
  Config derived from the actual cfg/.flake8 and cfg/.isort.cfg:
  line-length = 119, all existing ignores carried forward,
  Odoo-specific B006/B008 suppressed, odoo/odoo.addons mapped
  to known-first-party. skip-string-normalization wired from the
  same Copier variable already used by pyproject.toml.jinja.

• Three .jinja templates — ruff hooks added behind matrix gates:

  ruff_matrix_value	mandatory	autofix	optional
  < 20 (default)	flake8 only	black + autoflake + isort + pyupgrade	flake8 + bugbear
  >= 20	ruff + flake8	ruff check+format + legacy tools	ruff UP/SIM/RUF/C90 + flake8
  >= 30	ruff only	ruff only	ruff only

How to opt in

# Enable ruff alongside legacy tools (transition)
LINT_COMPATIBILITY_VERSION=10.10.10.10.10.10.10.20 pre-commit-vauxoo

# Enable ruff only, remove legacy tools
LINT_COMPATIBILITY_VERSION=10.10.10.10.10.10.10.30 pre-commit-vauxoo

Known behavioral delta

isort's ODOO / ODOO_ADDONS custom sections are not supported by
ruff's isort. Both are mapped to known-first-party; odoo and
odoo.addons imports merge into one group instead of two. Cosmetic
only — no CI failures. Documented in workspace/04-rule-mapping.md.

Tools replaced

┌────────────────┬───────────────────────────────────┐
│     Legacy     │          Ruff equivalent          │
├────────────────┼───────────────────────────────────┤
│ flake8         │ ruff check                        │
├────────────────┼───────────────────────────────────┤
│ flake8-bugbear │ ruff check (B rules)              │
├────────────────┼───────────────────────────────────┤
│ black          │ ruff format                       │
├────────────────┼───────────────────────────────────┤
│ isort          │ ruff check (I rules)              │
├────────────────┼───────────────────────────────────┤
│ autoflake      │ ruff check --fix (F401/F811/F841) │
├────────────────┼───────────────────────────────────┤
│ pyupgrade      │ ruff check --select UP            │
└────────────────┴───────────────────────────────────┘

pylint, pylint-odoo, OCA hooks, ESLint and Prettier are unchanged.

  [ADD] ruff integration via matrix position 8 (ruff_matrix_value)

Adds ruff as an opt-in linter/formatter via --compatibility-version.
Position 8 controls the behaviour:

  < 20 (default=10): disabled — existing consumers unaffected
  >= 20: ruff check+fix runs alongside flake8 and black (transition)
  >= 30: ruff replaces flake8/black/isort/autoflake/pyupgrade entirely

New config template ruff.toml.jinja:
  line-length=119, target-version=py310, select E/W/F/B/C4/I/UP/N.
  Ignores carried forward from .flake8 plus Odoo-specific B006/B008.
  isort: odoo+odoo.addons merged into first-party (cosmetic delta from
  legacy ODOO/ODOO_ADDONS sections — no lint impact).
  skip_string_normalization wired to ruff format quote-style.

Template changes:
  .pre-commit-config.yaml.jinja       ruff mandatory hook (>= 20), flake8 gated (< 30)
  .pre-commit-config-autofix.yaml.jinja  ruff check+fix (>= 20), ruff-format (>= 30),
                                         black/autoflake/isort/pyupgrade gated (< 30)
  .pre-commit-config-optional.yaml.jinja ruff SIM/RUF/C90 via --extend-select (>= 20),
                                         flake8-bugbear gated (< 30)

Deviations discovered during CI validation:
  1. ruff-format gated at >= 30, not >= 20. Running ruff-format and black
     simultaneously causes an infinite format loop: the two formatters
     disagree on wrapping point for multiline assert expressions. At
     value=20, ruff provides lint fixes only; black remains the formatter.
  2. B036 and E123 dropped from ignore list. Neither rule exists in ruff
     (rejected as "Unknown rule selector"). No practical impact.
  3. B018 added to __manifest__.py per-file-ignores. ruff B018 fires on
     Odoo manifest bare dict literals, which are intentional.
  4. Optional hook uses --extend-select, not --select. CLI --select
     overrides the config ignore list, re-triggering UP031.
  5. ci/bootstrap.py, docs/conf.py, pre_commit_vauxoo.py: .format() calls
     converted to f-strings (UP032). The docker test runs ruff on the
     repo's own source; these files had to comply.
  6. tests/test_pre_commit_vauxoo.py: two assert statements reformatted to
     a layout both black and ruff-format accept without conflict.

Benchmark (25 files, ruff 0.15.16 / black 26.5.1 / isort, Ubuntu 24.04):
  ruff check + ruff format              ~130 ms
  black + isort (partial legacy)        ~570 ms   (~4x faster)
  full legacy stack estimate
    (+ flake8 + autoflake + pyupgrade)  ~1270 ms  (~10x faster)

[hbto]

@moylop260 Could please review?

[hbto]

@moylop260 Done.