docs: correct four claims the README makes about the tool

[kmadan]

🚀 Overview

Corrects four claims README.md and README-pypi.md make about the tool that
do not match the repository or the code. Companion to #89, which carries the
same pass into the 19 files #88 did not touch. Documentation only.

📜 Changes Made

1. Python badge overstated the supported range

pyproject.toml declares requires-python = ">=3.12,<3.13" — 3.12 alone. The
badge read "Python 3.12+", advertising every later release as supported.
Now reads 3.12. The four translated READMEs carry the same fix in #89.

2. --evaluators was documented but has no effect

The options table listed it as a way to restrict the evaluator set.
_run_evaluate accepts the argument and never forwards it:

# aicertify/cli.py
async def _run_evaluate(..., evaluators: Optional[list] = None, ...):
    return await aicertify_app_for_policy(
        contract=contract, policy_folder=policy_folder,
        output_dir=output_dir, report_format=report_format,
        custom_params=custom_params,      # <- evaluators not passed
    )

A value supplied there has no effect on the run. The row is removed.

Left for a separate change: whether the flag should be wired through or
rejected outright is a behaviour question, not a docs one. The parser still
accepts it silently. Worth a follow-up issue.

3. Two of three linked output directories were empty

Link	Tracked files
examples/outputs/eu_ai_act/	0 — dead on GitHub
examples/outputs/medical_diagnosis/	1, a .gitkeep — renders empty
examples/outputs/loan_evaluation/	3, including a real PDF

Now links artefacts that are actually committed: the retained fair-lending PDF
and its contract, plus the three expected_report.md files under examples/.
The EU AI Act demo report was already linked directly above and is unchanged.

4. Regal link pointed at the old organisation

Regal moved from StyraInc to open-policy-agent. The link now points at the
current location (open-policy-agent/regal, 401 stars, active) rather than
relying on GitHub's redirect.

✅ Already fixed by #88 — not repeated here

• Policy count 85/91 → 92
• The "10-second demo" claim
• The CLI example now uses aicertify evaluate --policy uk (console script and
  framework name) rather than python -m aicertify.cli with a full policy path

🎯 How to Test

grep -c "3.12%2B\|--evaluators\|StyraInc" README.md README-pypi.md   # -> 0

Verified locally: every relative link in README.md resolves to a tracked
path, and none of 3.12+, --evaluators or StyraInc remains on either
surface.

📚 Documentation

• ✅ README.md, README-pypi.md
• ✅ No API, CLI or policy behaviour changes