refactor: Flatten directory structure

Move project files from uzdb/ subdirectory to root directory for cleaner project structure.

Changes:
- Move frontend/ to root
- Move internal/ to root
- Move build/ to root
- Move all config files (go.mod, wails.json, etc.) to root
- Remove redundant uzdb/ subdirectory nesting

Project structure is now:
├── frontend/        # React application
├── internal/        # Go backend
├── build/           # Wails build assets
├── doc/             # Design documentation
├── main.go          # Entry point
└── ...

🤖 Generated with Qoder

internal/models/response.go

@@ -0,0 +1,128 @@
+package models
+
+import (
+	"time"
+)
+
+// APIResponse represents a standard API response
+type APIResponse struct {
+	Success bool        `json:"success"`
+	Message string      `json:"message,omitempty"`
+	Data    interface{} `json:"data,omitempty"`
+	Error   string      `json:"error,omitempty"`
+}
+
+// QueryResult represents the result of a SQL query execution
+type QueryResult struct {
+	Columns      []string        `json:"columns"`
+	Rows         [][]interface{} `json:"rows"`
+	RowCount     int64           `json:"row_count"`
+	AffectedRows int64           `json:"affected_rows"`
+	Duration     int64           `json:"duration_ms"`
+	Success      bool            `json:"success"`
+	Error        string          `json:"error,omitempty"`
+}
+
+// Table represents a database table
+type Table struct {
+	Name        string `json:"name"`
+	Schema      string `json:"schema,omitempty"`
+	Type        string `json:"type"` // table, view, etc.
+	RowCount    int64  `json:"row_count,omitempty"`
+	Description string `json:"description,omitempty"`
+}
+
+// TableStructure represents the structure of a database table
+type TableStructure struct {
+	TableName string         `json:"table_name"`
+	Schema    string         `json:"schema,omitempty"`
+	Columns   []TableColumn  `json:"columns"`
+	Indexes   []TableIndex   `json:"indexes,omitempty"`
+	ForeignKeys []ForeignKey `json:"foreign_keys,omitempty"`
+}
+
+// TableColumn represents a column in a database table
+type TableColumn struct {
+	Name       string `json:"name"`
+	DataType   string `json:"data_type"`
+	Nullable   bool   `json:"nullable"`
+	Default    string `json:"default,omitempty"`
+	IsPrimary  bool   `json:"is_primary"`
+	IsUnique   bool   `json:"is_unique"`
+	AutoIncrement bool `json:"auto_increment"`
+	Length     int    `json:"length,omitempty"`
+	Scale      int    `json:"scale,omitempty"`
+	Comment    string `json:"comment,omitempty"`
+}
+
+// TableIndex represents an index on a database table
+type TableIndex struct {
+	Name      string   `json:"name"`
+	Columns   []string `json:"columns"`
+	IsUnique  bool     `json:"is_unique"`
+	IsPrimary bool     `json:"is_primary"`
+	Type      string   `json:"type,omitempty"`
+}
+
+// ForeignKey represents a foreign key constraint
+type ForeignKey struct {
+	Name              string   `json:"name"`
+	Columns           []string `json:"columns"`
+	ReferencedTable   string   `json:"referenced_table"`
+	ReferencedColumns []string `json:"referenced_columns"`
+	OnDelete          string   `json:"on_delete,omitempty"`
+	OnUpdate          string   `json:"on_update,omitempty"`
+}
+
+// ConnectionTestResult represents the result of a connection test
+type ConnectionTestResult struct {
+	Success  bool          `json:"success"`
+	Message  string        `json:"message"`
+	Duration int64         `json:"duration_ms"`
+	Metadata *DBMetadata   `json:"metadata,omitempty"`
+}
+
+// DBMetadata represents database metadata
+type DBMetadata struct {
+	Version    string `json:"version"`
+	Database   string `json:"database"`
+	User       string `json:"user"`
+	Host       string `json:"host"`
+	Port       int    `json:"port"`
+	ServerTime string `json:"server_time"`
+}
+
+// ErrorResponse represents an error response
+type ErrorResponse struct {
+	Error      string                 `json:"error"`
+	Message    string                 `json:"message"`
+	Code       string                 `json:"code,omitempty"`
+	Details    map[string]interface{} `json:"details,omitempty"`
+	Timestamp  time.Time              `json:"timestamp"`
+	Path       string                 `json:"path,omitempty"`
+}
+
+// PaginatedResponse represents a paginated response
+type PaginatedResponse struct {
+	Data       interface{} `json:"data"`
+	Total      int64       `json:"total"`
+	Page       int         `json:"page"`
+	PageSize   int         `json:"page_size"`
+	TotalPages int         `json:"total_pages"`
+}
+
+// NewAPIResponse creates a new API response
+func NewAPIResponse(data interface{}) *APIResponse {
+	return &APIResponse{
+		Success: true,
+		Data:    data,
+	}
+}
+
+// NewErrorResponse creates a new error response
+func NewErrorResponse(message string) *APIResponse {
+	return &APIResponse{
+		Success: false,
+		Error:   message,
+	}
+}