docs(06-02): complete Action Scheduler integration plan

Tasks completed: 2/2
- Download and include Action Scheduler library
- Create scheduler helper class for email batch actions

SUMMARY: .planning/phases/06-email-notifications/06-02-SUMMARY.md

.planning/phases/06-email-notifications/06-02-SUMMARY.md

@@ -0,0 +1,72 @@
+---
+phase: 06-email-notifications
+plan: 02
+subsystem: email
+tags: [action-scheduler, async-processing, email, batch-processing]
+requires: []
+provides: [async-email-infrastructure, batch-scheduling-api]
+affects: [06-03]
+tech-stack:
+  added: [action-scheduler-3.9.3]
+  patterns: [async-job-processing, batch-chunking]
+key-files:
+  created: [vendor/action-scheduler/, includes/class-scheduler.php]
+  modified: [ddhh-job-manager.php, includes/class-ddhh-job-manager.php]
+key-decisions: []
+issues-created: []
+duration: 1 min
+completed: 2026-01-14
+---
+
+# Phase 6 Plan 2: Action Scheduler Integration Summary
+
+**Action Scheduler 3.9.3 integrated with 50-user batch scheduling for async email processing**
+
+## Accomplishments
+
+- Downloaded and integrated Action Scheduler 3.9.3 library from WooCommerce GitHub
+- Library loaded early in main plugin file before other code for proper initialization
+- Created DDHH_JM_Scheduler helper class for managing async email batch actions
+- Implemented schedule_mentor_notification_batch() method that chunks users into batches of 50
+- Async actions enqueued with unique flag to prevent duplicates and email-notifications group for organization
+- Scheduler class initialized in main plugin lifecycle
+- Infrastructure ready for Phase 06-03 to implement actual email sending callbacks
+
+## Files Created/Modified
+
+- `vendor/action-scheduler/` - Action Scheduler 3.9.3 library (102 files, 17,820+ lines)
+- `includes/class-scheduler.php` - Scheduler helper class with batch scheduling API
+- `ddhh-job-manager.php` - Added Action Scheduler include before other code, added scheduler class include
+- `includes/class-ddhh-job-manager.php` - Initialized scheduler hooks in plugin lifecycle
+
+## Decisions Made
+
+None - straightforward implementation following Context7 best practices for Action Scheduler integration.
+
+## Issues Encountered
+
+None - library downloaded successfully, integration completed without errors.
+
+## Performance Data
+
+- Duration: 1 min
+- Started: 2026-01-14T12:03:24Z
+- Completed: 2026-01-14T12:04:35Z
+- Tasks completed: 2/2
+- Files modified: 4 files
+- Commits: 2 (1 per task)
+
+## Verification Results
+
+All verification criteria met:
+
+- [x] Action Scheduler library exists in vendor/action-scheduler/
+- [x] Library loaded in main plugin file before other includes
+- [x] Scheduler helper class created in includes/class-scheduler.php
+- [x] Batch scheduling method chunks users into batches of 50
+- [x] Action Scheduler functions available (as_enqueue_async_action works)
+- [x] No PHP errors on plugin activation (library auto-initializes)
+
+## Next Step
+
+Ready for Phase 06-03 (Email batch processing implementation). Phase 06-01 (Mentor opt-in) and 06-02 (Action Scheduler) are both complete and ready for 06-03 to build on.