Consolidating AI concepts into /ai — dropping the lossy duplicate from /concepts

Context

While auditing self-attack coverage, found that /concepts (the CONCEPTS array) actually held 202 cards — 136 real concept cards plus 66 AI cards with ai- prefixed ids and domain: "ai". Those 66 were built at module load by AI_CONCEPTS.map(...), and the map only copied a subset of fields: it kept title/ko/rawEn/explainEn/flow/code/probes but dropped probeAnswers and all the bilingual fields (and pinned the same generic three failureModes on all 66). The dedicated /ai deck (AI_CONCEPTS, 66 cards) had the full data including the model answers.

Verified with a tsx comparison that the two decks are the same content: id stems matched 66/66 (ai-token ↔ token), and title/ko/rawEn/code matched 66/66. The only difference was the missing probeAnswers on the /concepts copy. So on /concepts, 198 AI self-attack questions rendered with no model answer, while the identical questions on /ai had answers.

Options considered

1. Generate model answers for the 66 /concepts AI cards — fills the gap, keeps /concepts self-contained. Cost: an agent workflow (tokens) to write 198 answers; and it duplicates content that already exists answered on /ai, so two copies to maintain. Reversibility: easy.
2. Make /concepts reuse /ai's answered data — point the AI slot at the full AI_CONCEPTS objects instead of the lossy map. Single source, both pages complete. Cost: reconcile id/shape differences (the ai- prefix, domain tagging). Reversibility: medium.
3. Remove the AI domain from /concepts, consolidate into /ai — /ai is already the dedicated AI deck with full answers; drop the duplicate entirely. Cost: /concepts no longer lists AI topics (but they're one tab away on /ai). Reversibility: easy — re-add the spread.

Chosen + Why

Option 3. The duplicate was pure cost with no benefit: identical content, lossier, and a second place to keep in sync. /ai is the purpose-built AI deck (full bilingual fields, model answers, learning path), so it should be the single source. No content is lost — every AI topic stays on /ai, answered.

Trade-off accepted

/concepts no longer surfaces AI cards, so someone browsing only /concepts won't see AI topics inline; they have to go to /ai. Accepted because the two are separate tracks anyway and the duplicate was actively misleading (unanswered self-attacks).

Reversibility

Easy (two-way). Re-adding ...aiConcepts to the CONCEPTS spread and the ai domain restores the old behavior in one edit.

Verified by

• tsx audit pre-change: 202 cards, 66 ai- with 0 probeAnswers; content match 66/66 vs AI_CONCEPTS.
• tsx audit post-change: CONCEPTS = 136, 0 ai- ids, 0 domain==="ai", CONCEPT_DOMAINS has no ai; AI_CONCEPTS still 66, all answered.
• tsc --noEmit clean (after fixing two dangling "ai" references in lib/concept-sparring.ts).
• next build clean.
• Live (digest match, basic-auth): /concepts and /ai both 200; /concepts bundle no longer carries the AI token KO text; /ai bundle still does.

Discussion artifacts

Owner was asked (with trade-offs) how to handle the duplicate and chose "consolidate into /ai".

Commit

eac1931