fix: downgrade concept-type cleanup log from error to debug (#1606)

The parser correctly strips observation types from concepts arrays when the
LLM ignores the prompt instruction. This is routine data normalization, not
an error — downgrade to debug to reduce log noise.

Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/sdk/parser.ts

@@ -75,7 +75,7 @@ export function parseObservations(text: string, correlationId?: string): ParsedO
     const cleanedConcepts = concepts.filter(c => c !== finalType);
 
     if (cleanedConcepts.length !== concepts.length) {
-      logger.error('PARSER', 'Removed observation type from concepts array', {
+      logger.debug('PARSER', 'Removed observation type from concepts array', {
         correlationId,
         type: finalType,
         originalConcepts: concepts,