fix: validate platform keys at the gate and stop auto-register

Co-authored-by: Cursor <cursoragent@cursor.com>

assets/actions.json

@@ -2,6 +2,49 @@
   "schemaVersion": 1,
   "skill": "account-manager",
   "actions": [
+    {
+      "id": "platform-ensure",
+      "label": "新增平台",
+      "description": "登记平台：小写英文键 + 展示名必须分开。不会把中文名当成键。",
+      "replaces": "create",
+      "placements": [],
+      "executionProfile": "sync",
+      "interaction": "form",
+      "bind": {
+        "tables": ["platforms"]
+      },
+      "inputSchema": {
+        "type": "object",
+        "required": ["platform_key", "display_name"],
+        "properties": {
+          "platform_key": {
+            "type": "string",
+            "title": "平台键",
+            "description": "小写英文/数字/下划线或连字符，例如 douyin、deepseek。不要填中文。"
+          },
+          "display_name": {
+            "type": "string",
+            "title": "展示名称",
+            "description": "给人看的名称，可以是中文，例如 抖音。"
+          },
+          "default_url": {
+            "type": "string",
+            "title": "默认链接"
+          }
+        }
+      },
+      "steps": [{ "when": "afterSuccess", "do": "reloadTable" }],
+      "entrypoint": {
+        "type": "cli",
+        "command": "platform",
+        "args": [
+          "ensure",
+          "--key", "{{platform_key}}",
+          "--display-name", "{{display_name}}",
+          "--url", "{{default_url}}"
+        ]
+      }
+    },
     {
       "id": "account-add-web",
       "label": "新增账号",