fix(backup): proper backup/restore hooks + healthcheck start_period

- Add mysql_backup.sh: mysqldump to backup.sql.gz with proper restore hook
  (old --tab backup had no restore hook → restored backup silently lost DB data)
- Update db backupbot labels: pre-hook → /mysql_backup.sh backup,
  restore.post-hook → /mysql_backup.sh restore
- Fix app healthcheck start_period 1m → 15m (Ghost fresh-DB migration takes ~6-9min
  on slow hosts; old 1m caused migration lock deadlocks on deploy)
- Fix db healthcheck start_period 1m → 15m (InnoDB init on fresh data dir ~6-10min)
- Add MYSQL_BACKUP_VERSION=v1 to abra.sh

compose.yml

@@ -57,7 +57,7 @@ services:
       interval: 30s
       timeout: 10s
       retries: 10
-      start_period: 1m
+      start_period: 15m
  
   db:
     image: mysql:8.0
@@ -67,21 +67,25 @@ services:
       MYSQL_ROOT_PASSWORD_FILE: /run/secrets/db_password
     secrets:
       - db_password
+    configs:
+      - source: mysql_backup
+        target: /mysql_backup.sh
+        mode: 0555
     volumes:
       - "mysql:/var/lib/mysql"
     deploy:
       labels:
         - "backupbot.backup=true"
-        - "backupbot.backup.pre-hook=mysqldump -u root -p\"$$(cat /run/secrets/db_password)\" ghost --tab /var/lib/mysql-files/"
-        - "backupbot.backup.post-hook=rm -rf /var/lib/mysql-files/*"
-        - "backupbot.backup.path=/var/lib/mysql-files/"
+        - "backupbot.backup.pre-hook=/mysql_backup.sh backup"
+        - "backupbot.backup.volumes.mysql.path=backup.sql.gz"
+        - "backupbot.restore.post-hook=/mysql_backup.sh restore"
 
     healthcheck:
       test: ["CMD", "mysqladmin", "ping", "-h", "localhost", "-u", "root", "-p\"$$(cat /run/secrets/db_password)\""]
       interval: 30s
       timeout: 10s
       retries: 10
-      start_period: 1m
+      start_period: 15m
 
 networks:
   proxy:
@@ -103,4 +107,7 @@ secrets:
 configs:
   ghost_entrypoint:
     name: ${STACK_NAME}_ghost_entrypoint_${GHOST_ENTRYPOINT_VERSION}
-    file: entrypoint.sh
+    file: entrypoint.sh
+  mysql_backup:
+    name: ${STACK_NAME}_mysql_backup_${MYSQL_BACKUP_VERSION}
+    file: mysql_backup.sh