refactor: extract domain models from provider into internal/model

- Move Server/Domain/DNSRecord/Bucket/StorageInstance/CDNInstance/Order/Error structs to internal/model/
- Provider interfaces now reference model.* types
- Rainyun provider implementations import model package for data types
- CLI commands updated to use model.DNSRecord directly

Separates pure data structures from service contract interfaces,
following hexagonal architecture: models (entities) live independently
from ports (provider interfaces) and adapters (rainyun/* implementations).

internal/model/billing.go

@@ -0,0 +1,12 @@
+package model
+
+import "time"
+
+type Order struct {
+	ID      string    `json:"id"      table:"ID"`
+	Product string    `json:"product" table:"PRODUCT"`
+	Amount  float64   `json:"amount"  table:"AMOUNT"`
+	Status  string    `json:"status"  table:"STATUS"`
+	Created time.Time `json:"created" table:"CREATED"`
+	Raw     any       `json:"-"`
+}

internal/model/cdn.go

@@ -0,0 +1,8 @@
+package model
+
+type CDNInstance struct {
+	ID     string `json:"id"     table:"ID"`
+	Domain string `json:"domain" table:"DOMAIN"`
+	Status string `json:"status" table:"STATUS"`
+	Raw    any    `json:"-"`
+}

internal/model/domain.go

@@ -0,0 +1,19 @@
+package model
+
+import "time"
+
+type Domain struct {
+	ID       string    `json:"id"       table:"ID"`
+	Name     string    `json:"name"     table:"DOMAIN"`
+	Status   string    `json:"status"   table:"STATUS"`
+	ExpireAt time.Time `json:"expires"  table:"EXPIRES"`
+	Raw      any       `json:"-"`
+}
+
+type DNSRecord struct {
+	ID    string `json:"id"    table:"ID"`
+	Type  string `json:"type"  table:"TYPE"`
+	Name  string `json:"name"  table:"NAME"`
+	Value string `json:"value" table:"VALUE"`
+	TTL   int    `json:"ttl"   table:"TTL"`
+}

internal/model/errors.go

@@ -0,0 +1,18 @@
+package model
+
+import "fmt"
+
+type Error struct {
+	Code    int
+	Message string
+	Detail  string
+	Raw     []byte
+}
+
+func (e *Error) Error() string {
+	return e.Message
+}
+
+func (e *Error) Debug() string {
+	return fmt.Sprintf("%s\n%s", e.Detail, string(e.Raw))
+}

internal/model/server.go

@@ -0,0 +1,17 @@
+package model
+
+import "time"
+
+type Server struct {
+	ID       string    `json:"id"       table:"ID"`
+	Name     string    `json:"name"     table:"NAME"`
+	Status   string    `json:"status"   table:"STATUS"`
+	IP       string    `json:"ip"       table:"IP"`
+	CPU      int       `json:"cpu"      table:"CPU"`
+	Memory   int       `json:"memory"   table:"MEM"`
+	Disk     int       `json:"disk"     table:"DISK"`
+	OS       string    `json:"os"       table:"OS"`
+	Region   string    `json:"region"   table:"REGION"`
+	ExpireAt time.Time `json:"expires"  table:"EXPIRES"`
+	Raw      any       `json:"-"`
+}

internal/model/storage.go

@@ -0,0 +1,14 @@
+package model
+
+type StorageInstance struct {
+	ID     string `json:"id"     table:"ID"`
+	Name   string `json:"name"   table:"NAME"`
+	Status string `json:"status" table:"STATUS"`
+	Raw    any    `json:"-"`
+}
+
+type Bucket struct {
+	ID     string `json:"id"     table:"ID"`
+	Name   string `json:"name"   table:"NAME"`
+	Region string `json:"region" table:"REGION"`
+}