Add resumable LLM investigation loop with bounded controller execution

src/viano_bug_analysis/case/assembler.py

@@ -84,6 +84,14 @@ class CaseAssembler:
         prior_refs = []
         for _, checkpoint in reversed(chain):
             details = checkpoint["details"]
+            if details.get("operation")=="investigation-state":
+                for field in ("state_ref","context_ref","summary_ref"):
+                    ref=details.get(field)
+                    if ref is None:continue
+                    if not isinstance(ref,str) or not ref.startswith("analysis/investigation/"):
+                        raise CaseBuildError("PREVIOUS_CASE","Invalid investigation checkpoint")
+                    require_file(reader,ref)
+                    excluded.add(ref)
             if details.get("operation") == "evidence-stored":
                 refs = [details.get("index_ref"), details.get("request_ref"), details.get("result_ref"),
                         *details.get("record_refs", [])]