refactor: unify code formatting and improve push/search implementations

- Remove BOM from all Go source files
- Standardize import ordering and whitespace across handlers and services
- Replace PostgreSQL full-text search with ILIKE pattern matching in post and user repositories
- Enhance JPush client with TLS transport, rate limit monitoring, and simplified API
- Refactor PushService to include userID in device management methods
- Add MaxDevicesPerUser limit and extract helper functions for push payload construction

internal/repository/user_repo.go

@@ -439,9 +439,10 @@ func (r *userRepository) Search(keyword string, page, pageSize int) ([]*model.Us
 	// 搜索用户名、昵称、简介
 	if keyword != "" {
 		if r.db.Dialector.Name() == "postgres" {
+			searchPattern := "%" + keyword + "%"
 			query = query.Where(
-				"to_tsvector('simple', COALESCE(username, '') || ' ' || COALESCE(nickname, '') || ' ' || COALESCE(bio, '')) @@ plainto_tsquery('simple', ?)",
-				keyword,
+				"username ILIKE ? OR nickname ILIKE ? OR bio ILIKE ?",
+				searchPattern, searchPattern, searchPattern,
 			)
 		} else {
 			// SQLite: 使用 LOWER() 实现大小写不敏感的模糊搜索