Document Notarius cache reuse workflow

docs/troubleshooting.md

@@ -323,6 +323,59 @@ Do not point Notarius directly at the original source path or edit the manifest
 checksum. Relevant references: [Notarius reference configuration](./config.md#notarius-reference-bindings)
 and [Operations: Extraction Workflow](./operations.md#extraction-workflow).
 
+## Notarius reference snapshot cache conflict
+
+Symptom:
+
+- extraction reports that a path beneath
+  `cache/notarius/references/<sha256>/` is a symlink, directory, or another
+  non-regular or unsafe entry.
+
+Safe fix:
+
+- stop commands for the affected session and inspect the exact reported path;
+- investigate unexpected links or special files as possible tampering; and
+- remove only the reported conflicting leaf or digest directory after
+  confirming it belongs to the reconstructible reference cache.
+
+A missing snapshot or corrupt regular snapshot is reconstructed automatically
+from currently verified prepared input. Do not recursively delete the session
+root, edit the manifest checksum, or remove cache entries while extraction is
+active.
+
+Relevant reference: [Operations: Extraction Workflow](./operations.md#extraction-workflow).
+
+## Notarius resume executes work instead of reusing it
+
+Symptom:
+
+- Narratio executes `extract`, and Notarius makes provider calls despite
+  `pipeline.notarius.resume: true`.
+
+Likely causes:
+
+- checkpoint recording is disabled in the Notarius configuration;
+- Notarius is using a nonpersistent or different checkpoint root;
+- transcript/reference bytes, reference paths, pipeline/profile content,
+  local-backend endpoint, selected lanes, or another checkpoint identity input
+  changed; or
+- Narratio extraction was forced, which deliberately omits `--resume`.
+
+Safe fix:
+
+- validate the deployed Notarius configuration and configure explicit
+  persistent chunk-plan and checkpoint roots;
+- inspect Notarius checkpoint decision reason codes for a legitimate cold miss;
+  and
+- retry without force only when reuse is intended.
+
+Remember that Narratio skipping a completed `extract` stage is separate from
+Notarius reusing work inside an extraction that does execute. Narratio does not
+read the Notarius configuration to infer checkpoint enablement.
+
+Relevant references: [Notarius cache controls](./config.md#notarius-cache-controls)
+and [Notarius integration](./integrations/notarius.md).
+
 ## Notarius reference selector or generated-handoff collision
 
 Symptom: