feat(107-automation-email-send-once): idempotent send-once per order for email automation

Phase 107 complete:
- New table automation_email_once_deliveries with UNIQUE KEY (rule_id, action_id, order_id)
- AutomationEmailOnceRepository: wasSent() / markSent() with ON DUPLICATE KEY guard
- AutomationService: send_once_per_order flag — mark only on successful send
- Checkbox "Wyslij tylko raz dla tego zamowienia" in rule form (edit + new action JS)
- 2 unit tests added; 3/3 passing (49 assertions)

Milestone v3.1 Operational Enhancements: COMPLETE (2/2 phases)

Co-Authored-By: Claude <noreply@anthropic.com>

.paul/ROADMAP.md

@@ -6,18 +6,11 @@ orderPRO to narzedzie do wielokanalowego zarzadzania sprzedaza. Projekt przechod
 
 ## Current Milestone
 
-**v3.1 Operational Enhancements** (v3.1.0)
-Status: In progress
-Started: 2026-04-22
-
-| Phase | Name | Plans | Status |
-|-------|------|-------|--------|
-| 106 | Customer Return Alert | 1/1 | Complete |
-| 107 | Automation Email Send Once | 0/1 | Planning |
+Brak aktywnego milestone — v3.1 zamkniety. Nastepny milestone do zaplanowania.
 
 ## Next Milestone
 
-Kandydaci w kolejce (po zamknieciu v3.1):
+Kandydaci w kolejce:
 - Mobile Orders List / Mobile Order Details / Mobile Settings
 - Zarzadzanie produktami
 - Zarzadzanie stanami magazynowymi
@@ -26,6 +19,20 @@ Kandydaci w kolejce (po zamknieciu v3.1):
 
 ## Completed Milestones
 
+<details>
+<summary>v3.1 Operational Enhancements - 2026-04-27 (2 phases, 2 plans)</summary>
+
+Usprawnienia operacyjne: alert o kliencie z historia zwrotow oraz idempotentna jednorazowa wysylka e-mail per zamowienie.
+
+| Phase | Name | Plans | Status |
+|-------|------|-------|--------|
+| 106 | Customer Return Alert | 1/1 | Complete |
+| 107 | Automation Email Send Once | 1/1 | Complete |
+
+Archive: `.paul/phases/106-customer-return-alert/`, `.paul/phases/107-automation-email-send-once/`
+
+</details>
+
 <details>
 <summary>v3.0 Mobile Responsive - 2026-04-19 (52 phases shipped, 55 plans)</summary>