Add Helpdesk outbox worker validation

docs/redmineup_local_fork_changelog.md

@@ -27,11 +27,38 @@ environment. Before risky edits, archive the current plugin directories in
     manual browser testing.
   - Helpdesk mail import, Helpdesk metadata lookup, default non-email updates,
     and explicit outbound Helpdesk replies are live-smoke-tested through redMCP.
-  - Helpdesk outbox/worker validation is still pending.
+  - Helpdesk outbox/worker validation now has a repeatable live script.
 - Next meaningful milestone:
-  - Validate `redmine_outbox_worker.py` end to end against controlled Helpdesk
-    activity, document the derived JSONL shape, then choose the external index
-    target.
+  - Run `validate_helpdesk_outbox_worker.py` after outbox or worker changes,
+    then choose the external index target and durable processing policy.
+
+## 2026-04-25 - Helpdesk Outbox Worker Validation
+
+- Touched areas:
+  - Helpdesk test tooling
+  - External outbox worker validation docs
+- Purpose:
+  - Make Helpdesk outbox coverage repeatable after database refreshes and
+    worker changes.
+  - Validate worker enrichment against a real Mailpit-imported Helpdesk ticket
+    without claiming rows or marking them processed.
+- Behavior checked:
+  - Controlled Helpdesk import produces `helpdesk_ticket.created`,
+    `helpdesk_ticket.updated`, `journal_message.created`, `journal.created`,
+    and `issue.updated` rows.
+  - Worker dry-run enrichment emits `event`, `ticket`, and `message` documents.
+  - Derived message documents expose `has_bcc_address` but do not expose raw
+    `bcc_address`.
+- LAN test result:
+  - `./validate_helpdesk_outbox_worker.py` passed against `fud-helpdesk` and
+    `fud-nohelpdesk`.
+  - Latest documented passing run created and closed controlled Helpdesk issue
+    `#39873`.
+  - Observed outbox rows: 1 `helpdesk_ticket.created`, 3
+    `helpdesk_ticket.updated`, 1 `journal_message.created`, 3
+    `journal.created`, and 2 `issue.updated`.
+  - Worker dry-run enrichment produced 10 `event`, 6 `ticket`, and 2
+    `message` documents without claiming or marking rows processed.
 
 ## 2026-04-24 - Helpdesk/redMCP Smoke Validation