#Backfill and Fix NULL Columns in fact_records

Audit of fact_records revealed several columns systematically NULL due to pipeline gaps and missing wiring.

#Challenges

#Wave 1: Schema & Type Expansion

#	Challenge	PASS Criteria
1.1	Add notability fields to ImportFactsMessageSchema	Zod schema includes notability_score, notability_reason, context as optional fields
1.2	Update createImportFactsMessage TS type	TS type includes challenge_title?, notability_score?, notability_reason?, context?
1.3	Add generationCostUsd to insertFactRecord	Function accepts and writes generationCostUsd to DB

#Wave 2: Pipeline Wiring Fixes

#	Challenge	PASS Criteria
2.1	Enqueue GENERATE_CHALLENGE_CONTENT after validation	validate-fact.ts enqueues both RESOLVE_IMAGE and GENERATE_CHALLENGE_CONTENT for validated facts
2.2	Remove duplicate enqueue from import-facts.ts	import-facts.ts no longer imports or enqueues GENERATE_CHALLENGE_CONTENT; explanatory comment present
2.3	Wire notability fields through import pipeline	import-facts.ts passes notability_score, notability_reason, context from message to insertFactRecord; explode-entry.ts passes notability_score and context in IMPORT_FACTS items
2.4	Wire generationCostUsd in extraction handlers	extract-facts.ts computes cost via estimateCost() and passes to insertFactRecord; generate-evergreen.ts splits cost across records

#Wave 3: Backfill Existing Data

#	Challenge	PASS Criteria
3.1	Backfill notabilityScore for NULL records	--dry-run shows counts; --notability sets source-type defaults; verified with SELECT COUNT(*) WHERE notability_score IS NULL AND status = 'validated' returns 0
3.2	Enqueue challenge content for gaps	--challenge-content enqueues GENERATE_CHALLENGE_CONTENT for validated facts with zero fact_challenge_content rows
3.3	Audit data integrity	--audit reports anomalies: NULL validation JSONB, NULL publishedAt on validated records

#Verification

bun run typecheck
bun run test
bun run lint
bun scripts/seed/backfill-fact-nulls.ts --dry-run

#Files Modified

File	Change
packages/shared/src/schemas.ts	Added optional notability fields to ImportFactsMessageSchema
packages/queue/src/index.ts	Updated createImportFactsMessage TS type
packages/db/src/drizzle/fact-engine-queries.ts	Added generationCostUsd to insertFactRecord
apps/worker-validate/src/handlers/validate-fact.ts	Enqueue GENERATE_CHALLENGE_CONTENT after validation
apps/worker-facts/src/handlers/import-facts.ts	Wire notability fields, remove duplicate challenge enqueue
apps/worker-facts/src/handlers/explode-entry.ts	Pass notability/context to IMPORT_FACTS message
apps/worker-facts/src/handlers/extract-facts.ts	Wire generationCostUsd
apps/worker-facts/src/handlers/generate-evergreen.ts	Wire generationCostUsd
scripts/seed/backfill-fact-nulls.ts	NEW: Backfill script