feat: add certificate management module with image upload

- Add Certificate + CertificateCategory models with full CRUD API
- Image upload via base64 data URL stored in Text column
- Certificate fields: title, issuer, issue_date, expiry_date, image, description
- Frontend: card grid with category sidebar filter, create/edit dialog
- Include certificates in data backup/export
- Fix hasPhaseParent optimization in GoalDetailPage

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

api/app/routers/backup.py

@@ -16,8 +16,8 @@ router = APIRouter(prefix="/api/backup", tags=["备份"])
 # 导出顺序：按依赖关系（无 FK 的先导出）
 EXPORT_TABLES = [
     "categories", "tags", "user_settings", "sync_settings",
-    "habit_groups", "anniversary_categories",
-    "goals", "tasks", "habits", "anniversaries",
+    "habit_groups", "anniversary_categories", "certificate_categories",
+    "goals", "tasks", "habits", "anniversaries", "certificates",
     "goal_steps", "goal_reviews", "habit_checkins",
     "task_tags", "goal_tasks",
 ]
@@ -27,17 +27,17 @@ TRUNCATE_ORDER = [
     "task_tags", "goal_tasks",
     "habit_checkins",
     "goal_reviews", "goal_steps",
-    "tasks", "habits", "anniversaries",
+    "tasks", "habits", "anniversaries", "certificates",
     "goals", "categories", "tags",
-    "habit_groups", "anniversary_categories",
+    "habit_groups", "anniversary_categories", "certificate_categories",
     "user_settings", "sync_settings",
 ]
 
 # 导入时的插入顺序：父表先插
 INSERT_ORDER = [
     "categories", "tags", "user_settings", "sync_settings",
-    "habit_groups", "anniversary_categories",
-    "goals", "tasks", "habits", "anniversaries",
+    "habit_groups", "anniversary_categories", "certificate_categories",
+    "goals", "tasks", "habits", "anniversaries", "certificates",
     "goal_steps", "goal_reviews", "habit_checkins",
     "task_tags", "goal_tasks",
 ]