feat(128): erli orders import

Phase 128 complete:
- add Erli /inbox order import with safe mark-read ACK
- add cron/manual import controls and sync state tracking
- map Erli orders into orderPRO aggregates with mapper tests and docs

database/migrations/20260515_000115_add_erli_orders_import_schedule.sql

@@ -0,0 +1,29 @@
+CREATE TABLE IF NOT EXISTS integration_order_sync_state (
+    integration_id INT UNSIGNED NOT NULL PRIMARY KEY,
+    last_synced_order_updated_at DATETIME NULL,
+    last_synced_source_order_id VARCHAR(64) NULL,
+    last_synced_external_order_id VARCHAR(128) NULL,
+    last_run_at DATETIME NULL,
+    last_success_at DATETIME NULL,
+    last_error VARCHAR(500) NULL,
+    created_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP,
+    updated_at DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+    CONSTRAINT erli_integration_order_sync_state_integration_fk
+        FOREIGN KEY (integration_id) REFERENCES integrations(id)
+        ON DELETE CASCADE ON UPDATE CASCADE
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+
+ALTER TABLE integration_order_sync_state
+    ADD COLUMN IF NOT EXISTS last_synced_order_updated_at DATETIME NULL AFTER integration_id,
+    ADD COLUMN IF NOT EXISTS last_synced_source_order_id VARCHAR(64) NULL AFTER last_synced_order_updated_at,
+    ADD COLUMN IF NOT EXISTS last_success_at DATETIME NULL AFTER last_run_at;
+
+INSERT INTO cron_schedules (
+    job_type, interval_seconds, priority, max_attempts, payload, enabled, last_run_at, next_run_at, created_at, updated_at
+) VALUES (
+    'erli_orders_import', 300, 40, 3, NULL, 0, NULL, NOW(), NOW(), NOW()
+) ON DUPLICATE KEY UPDATE
+    interval_seconds = VALUES(interval_seconds),
+    priority = VALUES(priority),
+    max_attempts = VALUES(max_attempts),
+    updated_at = NOW();