Make Tane primary in README, VISION, CLAUDE, the intros and the
plain-language explainer (renamed que-es-tanemaki.md → que-es-tane.md,
dropping its "provisional name" caveats); keep Tanemaki (種まき) only as
the etymology.
PLAN.md is the origin record: its naming section §5-ter is preserved
verbatim as history under a dated "superseded" note, and the Nota de
vigencia now records Tane + the tane.comunes.org domain.
