Fix coverage with several contract classes; table annotation and file path checks; clean task dir on write

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014aUaQeLnwbb1zTpN7kHeat

tasks_gen/eval/G0121/seed/roasts.tabl.abap

@@ -0,0 +1,8 @@
+@EndUserText.label : 'Roast order line'
+@AbapCatalog.enhancement.category : #NOT_EXTENSIBLE
+define table {{p}}roasts {
+  key client   : abap.clnt not null;
+  key order_id : abap.numc(10) not null;
+  blend        : abap.char(4);
+  quantity_kg  : abap.dec(15,3);
+}