phase 17: fix datetime JSON serialization in aggregation worker market_context

.kiro/specs/stonks-oracle/tasks.md

@@ -198,7 +198,7 @@
   - Debug and fix any adapter errors (auth, rate limits, response parsing)
   - _Requirements: 4.1, 4.2, 4.3_
 
-- [-] 17.4 Validate parser normalizes documents and extractor produces intelligence
+- [x] 17.4 Validate parser normalizes documents and extractor produces intelligence
   - Check parser worker logs for document processing
   - Verify normalized text appears in MinIO `stonks-normalized` bucket
   - Verify `parse_quality_score` and `parse_confidence` are set on documents
@@ -208,7 +208,7 @@
   - Debug any Ollama connection or schema validation issues
   - _Requirements: 5.1, 5.2, 6.1, 6.2, 6.3_
 
-- [ ] 17.5 Validate aggregation produces trend summaries
+- [-] 17.5 Validate aggregation produces trend summaries
   - Check aggregation worker logs for trend window generation
   - Verify `trend_windows` table has entries with direction, strength, confidence
   - Verify `trend_evidence` table links trends to contributing documents

services/aggregation/worker.py

@@ -493,7 +493,7 @@ async def persist_trend_summary(
         json.dumps(summary.material_risks),
         summary.contradiction_score,
         json.dumps([d.model_dump() for d in summary.disagreement_details]),
-        json.dumps(summary.market_context.model_dump() if summary.market_context else {}),
+        json.dumps(summary.market_context.model_dump() if summary.market_context else {}, default=str),
         summary.generated_at,
     )
     return str(row["id"])