Provider reliability: opencode_zen model glm-4.6 -> claude-haiku-4-5 (valid) + reorder to working providers first (opencode_zen, huggingface, ...) so chat no longer depends on a single backend
Fix data hallucination: full-table store for ingested sheets/docs + strict no-invent prompt + 200-row default; chat answers aggregates (count/oldest) from complete data