Species framework remainder: language mechanics (per-character languages, granting, speech) + racial progression

[ApostateCD]

Gap

Two species-framework mechanics holes distinct from the content authoring tracked in #2764:

1. Language mechanics — Language exists and Species.grants_species_languages is flagged, and Species content buildout: Arvani Common language + elf/Daeva form traits #2463 authored the Arvani Common content, but nothing grants languages to characters: no per-character language storage (no CharacterLanguage or equivalent), no CG/heredity grant path, no speech integration (speaking/understanding a language in scenes, overhearing something you don't speak). Speech is culturally flat.
2. Racial progression — "growing stronger at racial abilities" from docs/roadmap/species.md. Species Minor Gifts ship at grant strength; there is no species-scoped advancement track anywhere in world/progression/ (verified — the only "racial" hit is help text).

Why

Languages are among the cheapest deep-culture signals a fantasy world has (and a natural secrets/eavesdropping hook); racial progression is what makes being khati/vampire/lycan a journey rather than a starting stat block.

Related: #2764 (content), #2463 (closed, Arvani Common content).