Implemented debug artifacts for the distributor notification adapter

docs/internal/state.md

@@ -47,6 +47,7 @@ converts adapter render results into that shape before saving.
 - `workspace.reports_dir`
 - `workspace.data_packages_dir`
 - `workspace.preflight_dir`
+- `workspace.notifications_dir`
 
 Workspace subdirectories must be relative paths that stay under
 `workspace.root`.
@@ -62,12 +63,14 @@ valid-period start date for JSON artifacts, and the RunID.
   snapshots/<artifact_group>/<YYYY-MM-DD>/<run_id>.metadata.json
   data-packages/<artifact_group>/<YYYY-MM-DD>/<run_id>.data_package.json
   preflight/<artifact_group>/<YYYY-MM-DD>/<run_id>.render.json
+  notifications/<artifact_group>/<YYYY-MM-DD>/<run_id>.distributor.json
   reports/<artifact_group>/<run_id>.md
 ```
 
 Metadata is stored beside briefing snapshots and links the briefing, data
-package, preflight, report paths, and configured prompt location. Report
-listing walks metadata files under the snapshots directory.
+package, preflight, report paths, notification path when attempted, and
+configured prompt location. Report listing walks metadata files under the
+snapshots directory.
 
 ## Prior Lookup
 
@@ -89,6 +92,8 @@ current report definition.
 Durable JSON writes use shared atomic file helpers. Managed Markdown reports are
 prepared by creating their parent directory; Scriptorium writes the report body
 to the prepared path. Extra Markdown copies are handled by app orchestration.
+Distributor notification debug artifacts are written atomically when
+notification is attempted.
 
 Inspection helpers read existing metadata, briefing, and data package files.
 Missing metadata directories return no inspection records or no prior snapshot