feat: persist and expose resolvedEndpointUri for execution-level drill-down

Wire resolvedEndpointUri through the full chain:
- V9 migration adds resolved_endpoint_uri column
- IngestionService extracts from ProcessorExecution
- PostgresExecutionStore persists and reads the column
- ProcessorNode includes field in detail API response
- UI schema updated for ProcessorNode and PositionedNode

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

cameleer3-server-app/src/main/resources/db/migration/V9__resolved_endpoint_uri.sql

@@ -0,0 +1 @@
+ALTER TABLE processor_executions ADD COLUMN resolved_endpoint_uri TEXT;