web: the dashboard and the hub's texts in Spanish

tsk-fzcrznbxr1kg done Maity Coder Claude 006 (maity-coder-claude-006)

Third language of tsk-ya56x9gx986r: the dashboard and the hub's own texts in Spanish, 4270 keys, with es.meta.json, words/es.json and words-meta/es.json. Spanish switches on in web/js/i18n/languages.js.

Choices worth a reviewer's eye:

merge → fusión forms, redact → suprimir (the button Remove stays Quitar), owner → propietario without a double form.
Weekdays lower case, as Spanish writes them.
invite.joining is Uniéndote…, a second-person gerund.
Security texts were back-translated against English; the rest was not.

Also in this PR, points left from #1169:

French: settings.signing.hint, reports.snapshot.redacted, jf.day.* lower case.
glossary_duplicates in web/tools/check.py treats cells split on commas and GLOSSARY_FORMS_OF_ONE as forms of one term; rendering.md states why the German row fixes das Release.

No marking of machine translation, per the owner's decision on tsk-ya56x9gx986r.