feat(adapters): 接入 CloudCone/Zeabur/Dynadot/新网/Agnes 五个平台

线上平台列表里 cloudcone、zeabur、xinwang、dynadot、agnes 的 sdk_type 仍为空，
平台卡片只能显示「未对接」，用户无法同步。按各自真实 API 能力补齐：

- CloudCone：实例清单 + 开机/关机/重启；无公开账单接口，不声明余额与续费
- Zeabur：服务器清单 + 重启；毫核/MB 归一化为核/GB，未采集时不伪造规格
- Dynadot：域名清单（含到期日）+ 账户余额；set_dns2 位置参数无法安全 CRUD
- 新网：代理 API 按域名逐个查到期日；无列表接口，需在账号里填 domains 清单
- Agnes：/models 校验 Key；无余额接口，如实标记不支持

配套改动：
- _align_preset_providers 为库中为空的 sdk_type 回填种子值（启动即生效），
  避免新适配器上线后线上仍停留在「未对接」
- 适配器可声明 plain_config，代理号/域名等非密钥字段前端按明文输入
- PRESET_PROVIDERS 五条记录填上对应 sdk_type

测试：445 passed（新增 tests/test_platform_adapters.py），vitest 62 passed。

tests/test_provider_alignment.py

@@ -26,8 +26,9 @@ from app.core.seed import PRESET_PROVIDERS, seed_providers
 from app.database import _align_preset_providers
 from app.models.provider import Provider
 
-#: 线上 GET /api/providers 抓下来的真实状态（2026-10-11），
-#: 用它做 fixture 才能保证迁移验证的是生产形态而不是理想形态
+#: 线上 GET /api/providers 抓下来的真实状态（2026-10-26），
+#: 用它做 fixture 才能保证迁移验证的是生产形态而不是理想形态。
+#: cloudcone/zeabur/dynadot/xinwang/agnes 上线前都是 None，靠启动迁移补 sdk_type。
 LIVE_PROVIDERS = [
     ("agnes", None, "ai_agent"),
     ("deepseek", "deepseek-api", "ai_agent"),
@@ -35,19 +36,19 @@ LIVE_PROVIDERS = [
     ("minimax", "minimax-api", "ai_agent"),
     ("openai", "openai-api", "ai_agent"),
     ("cloudflare", "cloudflare-api", "cloudflare,dns,ssl_cert,cdn"),
-    ("dynadot", "dynadot-api", "domain,dns"),
+    ("dynadot", None, "domain,dns"),
     ("namesilo", "namesilo-api", "domain,dns"),
     ("xinwang", None, "domain,dns"),
     ("aliyun", "aliyun-sdk", "vps,domain,ssl_cert,cdn,dns"),
     ("aliyun-intl", "alibabacloud-sdk", "vps,domain,ssl_cert,cdn,dns,ai_agent,other"),
-    ("cloudcone", "cloudcone-api", "vps"),
+    ("cloudcone", None, "vps"),
     ("digitalocean", "do-api", "vps,domain"),
     ("linode", "linode-api", "vps"),
     ("tencent", "tencent-sdk", "vps,domain,ssl_cert,cdn,dns"),
     ("tencent-intl", "tencent-intl-sdk", "vps,domain,ssl_cert,cdn,dns"),
-    ("tothost", None, "vps"),
+    ("tothost", "whmcs-panel", "vps"),
     ("vultr", "vultr-api", "vps"),
-    ("zeabur", "zeabur-api", "vps,domain"),
+    ("zeabur", None, "vps,domain"),
 ]
 
 
@@ -118,11 +119,25 @@ def test_seed_providers_is_idempotent(live_db):
 
 # ----------------------------- 迁移行为 ----------------------------- #
 def test_migration_clears_bogus_sdk_type(live_db):
-    """cloudcone/zeabur/dynadot 声明的适配器从未实现，必须清空"""
+    """库里声明了注册表没有的 sdk_type（旧版本残留）必须清空"""
+    with live_db.begin() as conn:
+        conn.execute(sa.text("UPDATE providers SET sdk_type = 'vultr-v1-removed' WHERE slug = 'vultr'"))
+    _run_migration(live_db)
+    assert _snapshot(live_db)["vultr"][0] is None
+
+
+def test_migration_backfills_missing_sdk_type(live_db):
+    """新增适配器上线后，库里 sdk_type 为空的预设平台必须补上，否则卡片永远不可同步"""
     _run_migration(live_db)
     snap = _snapshot(live_db)
-    for slug in ("cloudcone", "zeabur", "dynadot"):
-        assert snap[slug][0] is None, f"{slug}.sdk_type 未清空：{snap[slug][0]!r}"
+    for slug, expected in (
+        ("cloudcone", "cloudcone-api"),
+        ("zeabur", "zeabur-api"),
+        ("dynadot", "dynadot-api"),
+        ("xinwang", "xinnet-api"),
+        ("agnes", "agnes-api"),
+    ):
+        assert snap[slug][0] == expected, f"{slug}.sdk_type 未回填：{snap[slug][0]!r}"
 
 
 def test_migration_keeps_valid_sdk_type(live_db):
@@ -155,10 +170,13 @@ def test_migration_adds_missing_service_tags(live_db):
 
 
 def test_migration_ignores_user_created_providers(live_db):
-    """tothost 不在种子里，一个字都不能动"""
-    before = _snapshot(live_db)["tothost"]
+    """用户自建平台不在种子里，一个字都不能动"""
+    with Session(live_db) as s:
+        s.add(Provider(slug="myhost", name="MyHost", category="vps", services="vps"))
+        s.commit()
+    before = _snapshot(live_db)["myhost"]
     _run_migration(live_db)
-    assert _snapshot(live_db)["tothost"] == before
+    assert _snapshot(live_db)["myhost"] == before
 
 
 def test_migration_is_idempotent(live_db):