Start the Spanish rule reference — the index and the queryset family DOL001–DOL008 #99

A self-contained chunk of #52, and the one with the widest reach: docs/i18n/README.es.md is already translated, so Spanish readers arrive at the project in their own language and then hit an English-only rule reference.

What exists

docs/i18n/README.es.md — the project README in Spanish. Nothing under docs/i18n/rules/es/ yet.

What is missing

• docs/i18n/rules/es/README.md — the index. Without it a translated page has no entry point, so a reader who lands on one rule has no way to discover the rest.
• docs/i18n/rules/es/DOL001.md … DOL008.md — the queryset family, the most frequently triggered rules in the set.

The index alone is a genuinely useful first PR and takes an evening. Take that, or one family, or both — a PR per chunk is better than one large one.

Reference

• docs/i18n/rules/it/README.md is the model for starting a locale: it covers one family and says so plainly, linking out to the full English reference for the rest. That honesty is the right call when a locale covers 8 rules out of 22, and it is what this issue should copy.
• docs/i18n/rules/vi/ is the only complete locale — all 22 pages — so it shows what finished looks like.

Translate the prose, not the code

Python examples, rule codes, option names and suppression syntax stay byte-identical to the English source, so they stay copy-pasteable and greppable. django-orm-lens-disable-next-line is directive syntax, not prose — it does not get translated.

Two things checked on every translation PR, because a previous batch (#90) had to be rewritten for missing them:

• The index table repeats the canonical category, default severity and applicability from docs/rules/README.md unchanged. Translate the description, leave the metadata alone.
• Line count and heading structure track the English source.

Acceptance criteria

• Files land under docs/i18n/rules/es/.
• Code blocks, DOL*** codes and CLI flags are unchanged from the English source.
• docs/i18n/README.es.md links the new section.
• The PR confirms you read and write Spanish — I cannot review it myself.